lib/util/defaultProps.js
/**
* @fileoverview Common defaultProps detection functionality.
*/
'use strict';
const fromEntries = require('object.fromentries');
const astUtil = require('./ast');
const componentUtil = require('./componentUtil');
const propsUtil = require('./props');
const variableUtil = require('./variable');
const propWrapperUtil = require('./propWrapper');
const QUOTES_REGEX = /^["']|["']$/g;
module.exports = function defaultPropsInstructions(context, components, utils) {
const sourceCode = context.getSourceCode();
/**
* Try to resolve the node passed in to a variable in the current scope. If the node passed in is not
* an Identifier, then the node is simply returned.
* @param {ASTNode} node The node to resolve.
* @returns {ASTNode|null} Return null if the value could not be resolved, ASTNode otherwise.
*/
function resolveNodeValue(node) {
if (node.type === 'Identifier') {
return variableUtil.findVariableByName(context, node.name);
}
if (
node.type === 'CallExpression'
&& propWrapperUtil.isPropWrapperFunction(context, node.callee.name)
&& node.arguments && node.arguments[0]
) {
return resolveNodeValue(node.arguments[0]);
}
return node;
}
/**
* Extracts a DefaultProp from an ObjectExpression node.
* @param {ASTNode} objectExpression ObjectExpression node.
* @returns {Object|string} Object representation of a defaultProp, to be consumed by
* `addDefaultPropsToComponent`, or string "unresolved", if the defaultProps
* from this ObjectExpression can't be resolved.
*/
function getDefaultPropsFromObjectExpression(objectExpression) {
const hasSpread = objectExpression.properties.find((property) => property.type === 'ExperimentalSpreadProperty' || property.type === 'SpreadElement');
if (hasSpread) {
return 'unresolved';
}
return objectExpression.properties.map((defaultProp) => ({
name: sourceCode.getText(defaultProp.key).replace(QUOTES_REGEX, ''),
node: defaultProp,
}));
}
/**
* Marks a component's DefaultProps declaration as "unresolved". A component's DefaultProps is
* marked as "unresolved" if we cannot safely infer the values of its defaultProps declarations
* without risking false negatives.
* @param {Object} component The component to mark.
* @returns {void}
*/
function markDefaultPropsAsUnresolved(component) {
components.set(component.node, {
defaultProps: 'unresolved',
});
}
/**
* Adds defaultProps to the component passed in.
* @param {ASTNode} component The component to add the defaultProps to.
* @param {Object[]|'unresolved'} defaultProps defaultProps to add to the component or the string "unresolved"
* if this component has defaultProps that can't be resolved.
* @returns {void}
*/
function addDefaultPropsToComponent(component, defaultProps) {
// Early return if this component's defaultProps is already marked as "unresolved".
if (component.defaultProps === 'unresolved') {
return;
}
if (defaultProps === 'unresolved') {
markDefaultPropsAsUnresolved(component);
return;
}
const defaults = component.defaultProps || {};
const newDefaultProps = Object.assign(
{},
defaults,
fromEntries(defaultProps.map((prop) => [prop.name, prop]))
);
components.set(component.node, {
defaultProps: newDefaultProps,
});
}
return {
MemberExpression(node) {
const isDefaultProp = propsUtil.isDefaultPropsDeclaration(node);
if (!isDefaultProp) {
return;
}
// find component this defaultProps belongs to
const component = utils.getRelatedComponent(node);
if (!component) {
return;
}
// e.g.:
// MyComponent.propTypes = {
// foo: React.PropTypes.string.isRequired,
// bar: React.PropTypes.string
// };
//
// or:
//
// MyComponent.propTypes = myPropTypes;
if (node.parent.type === 'AssignmentExpression') {
const expression = resolveNodeValue(node.parent.right);
if (!expression || expression.type !== 'ObjectExpression') {
// If a value can't be found, we mark the defaultProps declaration as "unresolved", because
// we should ignore this component and not report any errors for it, to avoid false-positives
// with e.g. external defaultProps declarations.
if (isDefaultProp) {
markDefaultPropsAsUnresolved(component);
}
return;
}
addDefaultPropsToComponent(component, getDefaultPropsFromObjectExpression(expression));
return;
}
// e.g.:
// MyComponent.propTypes.baz = React.PropTypes.string;
if (node.parent.type === 'MemberExpression' && node.parent.parent
&& node.parent.parent.type === 'AssignmentExpression') {
addDefaultPropsToComponent(component, [{
name: node.parent.property.name,
node: node.parent.parent,
}]);
}
},
// e.g.:
// class Hello extends React.Component {
// static get defaultProps() {
// return {
// name: 'Dean'
// };
// }
// render() {
// return <div>Hello {this.props.name}</div>;
// }
// }
MethodDefinition(node) {
if (!node.static || node.kind !== 'get') {
return;
}
if (!propsUtil.isDefaultPropsDeclaration(node)) {
return;
}
// find component this propTypes/defaultProps belongs to
const component = components.get(componentUtil.getParentES6Component(context));
if (!component) {
return;
}
const returnStatement = utils.findReturnStatement(node);
if (!returnStatement) {
return;
}
const expression = resolveNodeValue(returnStatement.argument);
if (!expression || expression.type !== 'ObjectExpression') {
return;
}
addDefaultPropsToComponent(component, getDefaultPropsFromObjectExpression(expression));
},
// e.g.:
// class Greeting extends React.Component {
// render() {
// return (
// <h1>Hello, {this.props.foo} {this.props.bar}</h1>
// );
// }
// static defaultProps = {
// foo: 'bar',
// bar: 'baz'
// };
// }
'ClassProperty, PropertyDefinition'(node) {
if (!(node.static && node.value)) {
return;
}
const propName = astUtil.getPropertyName(node);
const isDefaultProp = propName === 'defaultProps' || propName === 'getDefaultProps';
if (!isDefaultProp) {
return;
}
// find component this propTypes/defaultProps belongs to
const component = components.get(componentUtil.getParentES6Component(context));
if (!component) {
return;
}
const expression = resolveNodeValue(node.value);
if (!expression || expression.type !== 'ObjectExpression') {
return;
}
addDefaultPropsToComponent(component, getDefaultPropsFromObjectExpression(expression));
},
// e.g.:
// React.createClass({
// render: function() {
// return <div>{this.props.foo}</div>;
// },
// getDefaultProps: function() {
// return {
// foo: 'default'
// };
// }
// });
ObjectExpression(node) {
// find component this propTypes/defaultProps belongs to
const component = componentUtil.isES5Component(node, context) && components.get(node);
if (!component) {
return;
}
// Search for the proptypes declaration
node.properties.forEach((property) => {
if (property.type === 'ExperimentalSpreadProperty' || property.type === 'SpreadElement') {
return;
}
const isDefaultProp = propsUtil.isDefaultPropsDeclaration(property);
if (isDefaultProp && property.value.type === 'FunctionExpression') {
const returnStatement = utils.findReturnStatement(property);
if (!returnStatement || returnStatement.argument.type !== 'ObjectExpression') {
return;
}
addDefaultPropsToComponent(component, getDefaultPropsFromObjectExpression(returnStatement.argument));
}
});
},
};
};