lib/mpath.js
'use strict';
/**
* Returns the value of object `o` at the given `path`.
*
* ####Example:
*
* var obj = {
* comments: [
* { title: 'exciting!', _doc: { title: 'great!' }}
* , { title: 'number dos' }
* ]
* }
*
* mpath.get('comments.0.title', o) // 'exciting!'
* mpath.get('comments.0.title', o, '_doc') // 'great!'
* mpath.get('comments.title', o) // ['exciting!', 'number dos']
*
* // summary
* mpath.get(path, o)
* mpath.get(path, o, special)
* mpath.get(path, o, map)
* mpath.get(path, o, special, map)
*
* @param {String} path
* @param {Object} o
* @param {String} [special] When this property name is present on any object in the path, walking will continue on the value of this property.
* @param {Function} [map] Optional function which receives each individual found value. The value returned from `map` is used in the original values place.
*/
exports.get = function (path, o, special, map) {
var lookup;
if ('function' === typeof special) {
if (special.length < 2) {
map = special;
special = undefined;
} else {
lookup = special;
special = undefined;
}
}
map || (map = K);
var parts = 'string' === typeof path
? path.split('.')
: path;
if (!Array.isArray(parts)) {
throw new TypeError('Invalid `path`. Must be either string or array');
}
var obj = o
, part;
for (var i = 0; i < parts.length; ++i) {
part = parts[i];
if (Array.isArray(obj) && !/^\d+$/.test(part)) {
// reading a property from the array items
var paths = parts.slice(i);
return obj.map(function (item) {
return item
? exports.get(paths, item, special || lookup, map)
: map(undefined);
});
}
if (lookup) {
obj = lookup(obj, part);
} else {
obj = special && obj[special]
? obj[special][part]
: obj[part];
}
if (!obj) return map(obj);
}
return map(obj);
};
/**
* Sets the `val` at the given `path` of object `o`.
*
* @param {String} path
* @param {*} val
* @param {Object} o
* @param {String} [special] When this property name is present on any object in the path, walking will continue on the value of this property.
* @param {Function} [map] Optional function which is passed each individual value before setting it. The value returned from `map` is used in the original values place.
*/
exports.set = function (path, val, o, special, map, _copying) {
var lookup;
if ('function' === typeof special) {
if (special.length < 2) {
map = special;
special = undefined;
} else {
lookup = special;
special = undefined;
}
}
map || (map = K);
var parts = 'string' === typeof path
? path.split('.')
: path;
if (!Array.isArray(parts)) {
throw new TypeError('Invalid `path`. Must be either string or array');
}
if (null == o) return;
// the existance of $ in a path tells us if the user desires
// the copying of an array instead of setting each value of
// the array to the one by one to matching positions of the
// current array.
var copy = _copying || /\$/.test(path)
, obj = o
, part;
for (var i = 0, len = parts.length - 1; i < len; ++i) {
part = parts[i];
if ('$' === part) {
if (i == len - 1) {
break;
} else {
continue;
}
}
if (Array.isArray(obj) && !/^\d+$/.test(part)) {
var paths = parts.slice(i);
if (!copy && Array.isArray(val)) {
for (var j = 0; j < obj.length && j < val.length; ++j) {
// assignment of single values of array
exports.set(paths, val[j], obj[j], special || lookup, map, copy);
}
} else {
for (var j = 0; j < obj.length; ++j) {
// assignment of entire value
exports.set(paths, val, obj[j], special || lookup, map, copy);
}
}
return;
}
if (lookup) {
obj = lookup(obj, part);
} else {
obj = special && obj[special]
? obj[special][part]
: obj[part];
}
if (!obj) return;
}
// process the last property of the path
part = parts[len];
// use the special property if exists
if (special && obj[special]) {
obj = obj[special];
}
// set the value on the last branch
if (Array.isArray(obj) && !/^\d+$/.test(part)) {
if (!copy && Array.isArray(val)) {
for (var item, j = 0; j < obj.length && j < val.length; ++j) {
item = obj[j];
if (item) {
if (lookup) {
lookup(item, part, map(val[j]));
} else {
if (item[special]) item = item[special];
item[part] = map(val[j]);
}
}
}
} else {
for (var j = 0; j < obj.length; ++j) {
item = obj[j];
if (item) {
if (lookup) {
lookup(item, part, map(val));
} else {
if (item[special]) item = item[special];
item[part] = map(val);
}
}
}
}
} else {
if (lookup) {
lookup(obj, part, map(val));
} else {
obj[part] = map(val);
}
}
};
/*!
* Returns the value passed to it.
*/
function K (v) {
return v;
}