getPathInfo.js
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/*!
* Chai - getPathInfo utility
* Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
* MIT Licensed
*/
var hasProperty = require('./hasProperty');
/**
* ### .getPathInfo(path, object)
*
* This allows the retrieval of property info in an
* object given a string path.
*
* The path info consists of an object with the
* following properties:
*
* * parent - The parent object of the property referenced by `path`
* * name - The name of the final property, a number if it was an array indexer
* * value - The value of the property, if it exists, otherwise `undefined`
* * exists - Whether the property exists or not
*
* @param {String} path
* @param {Object} object
* @returns {Object} info
* @name getPathInfo
* @api public
*/
module.exports = function getPathInfo(path, obj) {
var parsed = parsePath(path),
last = parsed[parsed.length - 1];
var info = {
parent: parsed.length > 1 ? _getPathValue(parsed, obj, parsed.length - 1) : obj,
name: last.p || last.i,
value: _getPathValue(parsed, obj),
};
info.exists = hasProperty(info.name, info.parent);
return info;
};
/*!
* ## parsePath(path)
*
* Helper function used to parse string object
* paths. Use in conjunction with `_getPathValue`.
*
* var parsed = parsePath('myobject.property.subprop');
*
* ### Paths:
*
* * Can be as near infinitely deep and nested
* * Arrays are also valid using the formal `myobject.document[3].property`.
* * Literal dots and brackets (not delimiter) must be backslash-escaped.
*
* @param {String} path
* @returns {Object} parsed
* @api private
*/
function parsePath (path) {
var str = path.replace(/([^\\])\[/g, '$1.[')
, parts = str.match(/(\\\.|[^.]+?)+/g);
return parts.map(function (value) {
var re = /^\[(\d+)\]$/
, mArr = re.exec(value);
if (mArr) return { i: parseFloat(mArr[1]) };
else return { p: value.replace(/\\([.\[\]])/g, '$1') };
});
}
/*!
* ## _getPathValue(parsed, obj)
*
* Helper companion function for `.parsePath` that returns
* the value located at the parsed address.
*
* var value = getPathValue(parsed, obj);
*
* @param {Object} parsed definition from `parsePath`.
* @param {Object} object to search against
* @param {Number} object to search against
* @returns {Object|Undefined} value
* @api private
*/
function _getPathValue (parsed, obj, index) {
var tmp = obj
, res;
index = (index === undefined ? parsed.length : index);
for (var i = 0, l = index; i < l; i++) {
var part = parsed[i];
if (tmp) {
if ('undefined' !== typeof part.p)
tmp = tmp[part.p];
else if ('undefined' !== typeof part.i)
tmp = tmp[part.i];
if (i == (l - 1)) res = tmp;
} else {
res = undefined;
}
}
return res;
}