huridocs/uwazi

title: max-statements ruletype: suggestion relatedrules: - complexity - max-depth - max-len - max-lines - max-lines-per-function - max-nested-callbacks

- max-params

The max-statements rule allows you to specify the maximum number of statements allowed in a function.

function foo() {
  var bar = 1; // one statement
  var baz = 2; // two statements
  var qux = 3; // three statements
}

Rule Details

This rule enforces a maximum number of statements allowed in function blocks.

Options

This rule has a number or object option:

• "max" (default 10) enforces a maximum number of statements allows in function blocks

Deprecated: The object property maximum is deprecated; please use the object property max instead.

This rule has an object option:

• "ignoreTopLevelFunctions": true ignores top-level functions

max

Examples of incorrect code for this rule with the default { "max": 10 } option:

::: incorrect

/*eslint max-statements: ["error", 10]*/
/*eslint-env es6*/

function foo() {
  var foo1 = 1;
  var foo2 = 2;
  var foo3 = 3;
  var foo4 = 4;
  var foo5 = 5;
  var foo6 = 6;
  var foo7 = 7;
  var foo8 = 8;
  var foo9 = 9;
  var foo10 = 10;

  var foo11 = 11; // Too many.
}

let foo = () => {
  var foo1 = 1;
  var foo2 = 2;
  var foo3 = 3;
  var foo4 = 4;
  var foo5 = 5;
  var foo6 = 6;
  var foo7 = 7;
  var foo8 = 8;
  var foo9 = 9;
  var foo10 = 10;

  var foo11 = 11; // Too many.
};

:::

Examples of correct code for this rule with the default { "max": 10 } option:

::: correct

/*eslint max-statements: ["error", 10]*/
/*eslint-env es6*/

function foo() {
  var foo1 = 1;
  var foo2 = 2;
  var foo3 = 3;
  var foo4 = 4;
  var foo5 = 5;
  var foo6 = 6;
  var foo7 = 7;
  var foo8 = 8;
  var foo9 = 9;
  var foo10 = 10;
  return function () {

    // The number of statements in the inner function does not count toward the
    // statement maximum.

    return 42;
  };
}

let foo = () => {
  var foo1 = 1;
  var foo2 = 2;
  var foo3 = 3;
  var foo4 = 4;
  var foo5 = 5;
  var foo6 = 6;
  var foo7 = 7;
  var foo8 = 8;
  var foo9 = 9;
  var foo10 = 10;
  return function () {

    // The number of statements in the inner function does not count toward the
    // statement maximum.

    return 42;
  };
}

:::

Note that this rule does not apply to class static blocks, and that statements in class static blocks do not count as statements in the enclosing function.

Examples of correct code for this rule with { "max": 2 } option:

::: correct

/*eslint max-statements: ["error", 2]*/

function foo() {
    let one;
    let two = class {
        static {
            let three;
            let four;
            let five;
            if (six) {
                let seven;
                let eight;
                let nine;
            }
        }
    };
}

:::

ignoreTopLevelFunctions

Examples of additional correct code for this rule with the { "max": 10 }, { "ignoreTopLevelFunctions": true } options:

::: correct

/*eslint max-statements: ["error", 10, { "ignoreTopLevelFunctions": true }]*/

function foo() {
  var foo1 = 1;
  var foo2 = 2;
  var foo3 = 3;
  var foo4 = 4;
  var foo5 = 5;
  var foo6 = 6;
  var foo7 = 7;
  var foo8 = 8;
  var foo9 = 9;
  var foo10 = 10;
  var foo11 = 11;
}

::: Source: http://eslint.org/docs/rules/

title: func-names ruletype: suggestion furtherreading: - https://web.archive.org/web/20201112040809/http://markdaggett.com/blog/2013/02/15/functions-explained/

- https://2ality.com/2015/09/function-names-es6.html

A pattern that's becoming more common is to give function expressions names to aid in debugging. For example:

Foo.prototype.bar = function bar() {};

Adding the second bar in the above example is optional. If you leave off the function name then when the function throws an exception you are likely to get something similar to anonymous function in the stack trace. If you provide the optional name for a function expression then you will get the name of the function expression in the stack trace.

Rule Details

This rule can enforce or disallow the use of named function expressions.

Options

This rule has a string option:

• "always" (default) requires function expressions to have a name
• "as-needed" requires function expressions to have a name, if the name isn't assigned automatically per the ECMAScript specification.
• "never" disallows named function expressions, except in recursive functions, where a name is needed

This rule has an object option:

• "generators": "always" | "as-needed" | "never"
  • "always" require named generators
  • "as-needed" require named generators if the name isn't assigned automatically per the ECMAScript specification.
  • "never" disallow named generators where possible.

When a value for generators is not provided the behavior for generator functions falls back to the base option.

Please note that "always" and "as-needed" require function expressions and function declarations in export default declarations to have a name.

always

Examples of incorrect code for this rule with the default "always" option:

::: incorrect

/*eslint func-names: ["error", "always"]*/

Foo.prototype.bar = function() {};

const cat = {
  meow: function() {}
}

(function() {
    // ...
}())

export default function() {}

:::

Examples of correct code for this rule with the default "always" option:

::: correct

/*eslint func-names: ["error", "always"]*/

Foo.prototype.bar = function bar() {};

const cat = {
  meow() {}
}

(function bar() {
    // ...
}())

export default function foo() {}

:::

as-needed

ECMAScript 6 introduced a name property on all functions. The value of name is determined by evaluating the code around the function to see if a name can be inferred. For example, a function assigned to a variable will automatically have a name property equal to the name of the variable. The value of name is then used in stack traces for easier debugging.

Examples of incorrect code for this rule with the "as-needed" option:

::: incorrect

/*eslint func-names: ["error", "as-needed"]*/

Foo.prototype.bar = function() {};

(function() {
    // ...
}())

export default function() {}

:::

Examples of correct code for this rule with the "as-needed" option:

::: correct

/*eslint func-names: ["error", "as-needed"]*/

var bar = function() {};

const cat = {
  meow: function() {}
}

class C {
    #bar = function() {};
    baz = function() {};
}

quux ??= function() {};

(function bar() {
    // ...
}())

export default function foo() {}

:::

never

Examples of incorrect code for this rule with the "never" option:

::: incorrect

/*eslint func-names: ["error", "never"]*/

Foo.prototype.bar = function bar() {};

(function bar() {
    // ...
}())

:::

Examples of correct code for this rule with the "never" option:

::: correct

/*eslint func-names: ["error", "never"]*/

Foo.prototype.bar = function() {};

(function() {
    // ...
}())

:::

generators

Examples of incorrect code for this rule with the "always", { "generators": "as-needed" } options:

::: incorrect

/*eslint func-names: ["error", "always", { "generators": "as-needed" }]*/

(function*() {
    // ...
}())

:::

Examples of correct code for this rule with the "always", { "generators": "as-needed" } options:

::: correct

/*eslint func-names: ["error", "always", { "generators": "as-needed" }]*/

var foo = function*() {};

:::

Examples of incorrect code for this rule with the "always", { "generators": "never" } options:

::: incorrect

/*eslint func-names: ["error", "always", { "generators": "never" }]*/

var foo = bar(function *baz() {});

:::

Examples of correct code for this rule with the "always", { "generators": "never" } options:

::: correct

/*eslint func-names: ["error", "always", { "generators": "never" }]*/

var foo = bar(function *() {});

:::

Examples of incorrect code for this rule with the "as-needed", { "generators": "never" } options:

::: incorrect

/*eslint func-names: ["error", "as-needed", { "generators": "never" }]*/

var foo = bar(function *baz() {});

:::

Examples of correct code for this rule with the "as-needed", { "generators": "never" } options:

::: correct

/*eslint func-names: ["error", "as-needed", { "generators": "never" }]*/

var foo = bar(function *() {});

:::

Examples of incorrect code for this rule with the "never", { "generators": "always" } options:

::: incorrect

/*eslint func-names: ["error", "never", { "generators": "always" }]*/

var foo = bar(function *() {});

:::

Examples of correct code for this rule with the "never", { "generators": "always" } options:

::: correct

/*eslint func-names: ["error", "never", { "generators": "always" }]*/

var foo = bar(function *baz() {});

:::

Compatibility

• JSCS: requireAnonymousFunctions
• JSCS: disallowAnonymousFunctions Source: http://eslint.org/docs/rules/

title: func-names ruletype: suggestion furtherreading: - https://web.archive.org/web/20201112040809/http://markdaggett.com/blog/2013/02/15/functions-explained/

- https://2ality.com/2015/09/function-names-es6.html

A pattern that's becoming more common is to give function expressions names to aid in debugging. For example:

Foo.prototype.bar = function bar() {};

Adding the second bar in the above example is optional. If you leave off the function name then when the function throws an exception you are likely to get something similar to anonymous function in the stack trace. If you provide the optional name for a function expression then you will get the name of the function expression in the stack trace.

Rule Details

This rule can enforce or disallow the use of named function expressions.

Options

This rule has a string option:

• "always" (default) requires function expressions to have a name
• "as-needed" requires function expressions to have a name, if the name isn't assigned automatically per the ECMAScript specification.
• "never" disallows named function expressions, except in recursive functions, where a name is needed

This rule has an object option:

• "generators": "always" | "as-needed" | "never"
  • "always" require named generators
  • "as-needed" require named generators if the name isn't assigned automatically per the ECMAScript specification.
  • "never" disallow named generators where possible.

When a value for generators is not provided the behavior for generator functions falls back to the base option.

Please note that "always" and "as-needed" require function expressions and function declarations in export default declarations to have a name.

always

Examples of incorrect code for this rule with the default "always" option:

::: incorrect

/*eslint func-names: ["error", "always"]*/

Foo.prototype.bar = function() {};

const cat = {
  meow: function() {}
}

(function() {
    // ...
}())

export default function() {}

:::

Examples of correct code for this rule with the default "always" option:

::: correct

/*eslint func-names: ["error", "always"]*/

Foo.prototype.bar = function bar() {};

const cat = {
  meow() {}
}

(function bar() {
    // ...
}())

export default function foo() {}

:::

as-needed

ECMAScript 6 introduced a name property on all functions. The value of name is determined by evaluating the code around the function to see if a name can be inferred. For example, a function assigned to a variable will automatically have a name property equal to the name of the variable. The value of name is then used in stack traces for easier debugging.

Examples of incorrect code for this rule with the "as-needed" option:

::: incorrect

/*eslint func-names: ["error", "as-needed"]*/

Foo.prototype.bar = function() {};

(function() {
    // ...
}())

export default function() {}

:::

Examples of correct code for this rule with the "as-needed" option:

::: correct

/*eslint func-names: ["error", "as-needed"]*/

var bar = function() {};

const cat = {
  meow: function() {}
}

class C {
    #bar = function() {};
    baz = function() {};
}

quux ??= function() {};

(function bar() {
    // ...
}())

export default function foo() {}

:::

never

Examples of incorrect code for this rule with the "never" option:

::: incorrect

/*eslint func-names: ["error", "never"]*/

Foo.prototype.bar = function bar() {};

(function bar() {
    // ...
}())

:::

Examples of correct code for this rule with the "never" option:

::: correct

/*eslint func-names: ["error", "never"]*/

Foo.prototype.bar = function() {};

(function() {
    // ...
}())

:::

generators

Examples of incorrect code for this rule with the "always", { "generators": "as-needed" } options:

::: incorrect

/*eslint func-names: ["error", "always", { "generators": "as-needed" }]*/

(function*() {
    // ...
}())

:::

Examples of correct code for this rule with the "always", { "generators": "as-needed" } options:

::: correct

/*eslint func-names: ["error", "always", { "generators": "as-needed" }]*/

var foo = function*() {};

:::

Examples of incorrect code for this rule with the "always", { "generators": "never" } options:

::: incorrect

/*eslint func-names: ["error", "always", { "generators": "never" }]*/

var foo = bar(function *baz() {});

:::

Examples of correct code for this rule with the "always", { "generators": "never" } options:

::: correct

/*eslint func-names: ["error", "always", { "generators": "never" }]*/

var foo = bar(function *() {});

:::

Examples of incorrect code for this rule with the "as-needed", { "generators": "never" } options:

::: incorrect

/*eslint func-names: ["error", "as-needed", { "generators": "never" }]*/

var foo = bar(function *baz() {});

:::

Examples of correct code for this rule with the "as-needed", { "generators": "never" } options:

::: correct

/*eslint func-names: ["error", "as-needed", { "generators": "never" }]*/

var foo = bar(function *() {});

:::

Examples of incorrect code for this rule with the "never", { "generators": "always" } options:

::: incorrect

/*eslint func-names: ["error", "never", { "generators": "always" }]*/

var foo = bar(function *() {});

:::

Examples of correct code for this rule with the "never", { "generators": "always" } options:

::: correct

/*eslint func-names: ["error", "never", { "generators": "always" }]*/

var foo = bar(function *baz() {});

:::

Compatibility

• JSCS: requireAnonymousFunctions
• JSCS: disallowAnonymousFunctions Source: http://eslint.org/docs/rules/

title: func-names ruletype: suggestion furtherreading: - https://web.archive.org/web/20201112040809/http://markdaggett.com/blog/2013/02/15/functions-explained/

- https://2ality.com/2015/09/function-names-es6.html

A pattern that's becoming more common is to give function expressions names to aid in debugging. For example:

Foo.prototype.bar = function bar() {};

Adding the second bar in the above example is optional. If you leave off the function name then when the function throws an exception you are likely to get something similar to anonymous function in the stack trace. If you provide the optional name for a function expression then you will get the name of the function expression in the stack trace.

Rule Details

This rule can enforce or disallow the use of named function expressions.

Options

This rule has a string option:

• "always" (default) requires function expressions to have a name
• "as-needed" requires function expressions to have a name, if the name isn't assigned automatically per the ECMAScript specification.
• "never" disallows named function expressions, except in recursive functions, where a name is needed

This rule has an object option:

• "generators": "always" | "as-needed" | "never"
  • "always" require named generators
  • "as-needed" require named generators if the name isn't assigned automatically per the ECMAScript specification.
  • "never" disallow named generators where possible.

When a value for generators is not provided the behavior for generator functions falls back to the base option.

Please note that "always" and "as-needed" require function expressions and function declarations in export default declarations to have a name.

always

Examples of incorrect code for this rule with the default "always" option:

::: incorrect

/*eslint func-names: ["error", "always"]*/

Foo.prototype.bar = function() {};

const cat = {
  meow: function() {}
}

(function() {
    // ...
}())

export default function() {}

:::

Examples of correct code for this rule with the default "always" option:

::: correct

/*eslint func-names: ["error", "always"]*/

Foo.prototype.bar = function bar() {};

const cat = {
  meow() {}
}

(function bar() {
    // ...
}())

export default function foo() {}

:::

as-needed

ECMAScript 6 introduced a name property on all functions. The value of name is determined by evaluating the code around the function to see if a name can be inferred. For example, a function assigned to a variable will automatically have a name property equal to the name of the variable. The value of name is then used in stack traces for easier debugging.

Examples of incorrect code for this rule with the "as-needed" option:

::: incorrect

/*eslint func-names: ["error", "as-needed"]*/

Foo.prototype.bar = function() {};

(function() {
    // ...
}())

export default function() {}

:::

Examples of correct code for this rule with the "as-needed" option:

::: correct

/*eslint func-names: ["error", "as-needed"]*/

var bar = function() {};

const cat = {
  meow: function() {}
}

class C {
    #bar = function() {};
    baz = function() {};
}

quux ??= function() {};

(function bar() {
    // ...
}())

export default function foo() {}

:::

never

Examples of incorrect code for this rule with the "never" option:

::: incorrect

/*eslint func-names: ["error", "never"]*/

Foo.prototype.bar = function bar() {};

(function bar() {
    // ...
}())

:::

Examples of correct code for this rule with the "never" option:

::: correct

/*eslint func-names: ["error", "never"]*/

Foo.prototype.bar = function() {};

(function() {
    // ...
}())

:::

generators

Examples of incorrect code for this rule with the "always", { "generators": "as-needed" } options:

::: incorrect

/*eslint func-names: ["error", "always", { "generators": "as-needed" }]*/

(function*() {
    // ...
}())

:::

Examples of correct code for this rule with the "always", { "generators": "as-needed" } options:

::: correct

/*eslint func-names: ["error", "always", { "generators": "as-needed" }]*/

var foo = function*() {};

:::

Examples of incorrect code for this rule with the "always", { "generators": "never" } options:

::: incorrect

/*eslint func-names: ["error", "always", { "generators": "never" }]*/

var foo = bar(function *baz() {});

:::

Examples of correct code for this rule with the "always", { "generators": "never" } options:

::: correct

/*eslint func-names: ["error", "always", { "generators": "never" }]*/

var foo = bar(function *() {});

:::

Examples of incorrect code for this rule with the "as-needed", { "generators": "never" } options:

::: incorrect

/*eslint func-names: ["error", "as-needed", { "generators": "never" }]*/

var foo = bar(function *baz() {});

:::

Examples of correct code for this rule with the "as-needed", { "generators": "never" } options:

::: correct

/*eslint func-names: ["error", "as-needed", { "generators": "never" }]*/

var foo = bar(function *() {});

:::

Examples of incorrect code for this rule with the "never", { "generators": "always" } options:

::: incorrect

/*eslint func-names: ["error", "never", { "generators": "always" }]*/

var foo = bar(function *() {});

:::

Examples of correct code for this rule with the "never", { "generators": "always" } options:

::: correct

/*eslint func-names: ["error", "never", { "generators": "always" }]*/

var foo = bar(function *baz() {});

:::

Compatibility

• JSCS: requireAnonymousFunctions
• JSCS: disallowAnonymousFunctions Source: http://eslint.org/docs/rules/

title: no-cond-assign ruletype: problem relatedrules:

- no-extra-parens

In conditional statements, it is very easy to mistype a comparison operator (such as ==) as an assignment operator (such as =). For example:

// Check the user's job title
if (user.jobTitle = "manager") {
    // user.jobTitle is now incorrect
}

There are valid reasons to use assignment operators in conditional statements. However, it can be difficult to tell whether a specific assignment was intentional.

Rule Details

This rule disallows ambiguous assignment operators in test conditions of if, for, while, and do...while statements.

Options

This rule has a string option:

• "except-parens" (default) allows assignments in test conditions only if they are enclosed in parentheses (for example, to allow reassigning a variable in the test of a while or do...while loop)
• "always" disallows all assignments in test conditions

except-parens

Examples of incorrect code for this rule with the default "except-parens" option:

::: incorrect

/*eslint no-cond-assign: "error"*/

// Unintentional assignment
var x;
if (x = 0) {
    var b = 1;
}

// Practical example that is similar to an error
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while (someNode = someNode.parentNode);
}

:::

Examples of correct code for this rule with the default "except-parens" option:

::: correct

/*eslint no-cond-assign: "error"*/

// Assignment replaced by comparison
var x;
if (x === 0) {
    var b = 1;
}

// Practical example that wraps the assignment in parentheses
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode));
}

// Practical example that wraps the assignment and tests for 'null'
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode) !== null);
}

:::

always

Examples of incorrect code for this rule with the "always" option:

::: incorrect

/*eslint no-cond-assign: ["error", "always"]*/

// Unintentional assignment
var x;
if (x = 0) {
    var b = 1;
}

// Practical example that is similar to an error
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while (someNode = someNode.parentNode);
}

// Practical example that wraps the assignment in parentheses
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode));
}

// Practical example that wraps the assignment and tests for 'null'
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode) !== null);
}

:::

Examples of correct code for this rule with the "always" option:

::: correct

/*eslint no-cond-assign: ["error", "always"]*/

// Assignment replaced by comparison
var x;
if (x === 0) {
    var b = 1;
}

::: Source: http://eslint.org/docs/rules/

title: no-cond-assign ruletype: problem relatedrules:

- no-extra-parens

In conditional statements, it is very easy to mistype a comparison operator (such as ==) as an assignment operator (such as =). For example:

// Check the user's job title
if (user.jobTitle = "manager") {
    // user.jobTitle is now incorrect
}

There are valid reasons to use assignment operators in conditional statements. However, it can be difficult to tell whether a specific assignment was intentional.

Rule Details

This rule disallows ambiguous assignment operators in test conditions of if, for, while, and do...while statements.

Options

This rule has a string option:

• "except-parens" (default) allows assignments in test conditions only if they are enclosed in parentheses (for example, to allow reassigning a variable in the test of a while or do...while loop)
• "always" disallows all assignments in test conditions

except-parens

Examples of incorrect code for this rule with the default "except-parens" option:

::: incorrect

/*eslint no-cond-assign: "error"*/

// Unintentional assignment
var x;
if (x = 0) {
    var b = 1;
}

// Practical example that is similar to an error
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while (someNode = someNode.parentNode);
}

:::

Examples of correct code for this rule with the default "except-parens" option:

::: correct

/*eslint no-cond-assign: "error"*/

// Assignment replaced by comparison
var x;
if (x === 0) {
    var b = 1;
}

// Practical example that wraps the assignment in parentheses
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode));
}

// Practical example that wraps the assignment and tests for 'null'
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode) !== null);
}

:::

always

Examples of incorrect code for this rule with the "always" option:

::: incorrect

/*eslint no-cond-assign: ["error", "always"]*/

// Unintentional assignment
var x;
if (x = 0) {
    var b = 1;
}

// Practical example that is similar to an error
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while (someNode = someNode.parentNode);
}

// Practical example that wraps the assignment in parentheses
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode));
}

// Practical example that wraps the assignment and tests for 'null'
function setHeight(someNode) {
    "use strict";
    do {
        someNode.height = "100px";
    } while ((someNode = someNode.parentNode) !== null);
}

:::

Examples of correct code for this rule with the "always" option:

::: correct

/*eslint no-cond-assign: ["error", "always"]*/

// Assignment replaced by comparison
var x;
if (x === 0) {
    var b = 1;
}

::: Source: http://eslint.org/docs/rules/

For more information visit Source: http://eslint.org/docs/rules/

For more information visit Source: http://eslint.org/docs/rules/