node-query/lib/helpers.js

126 lines
2.9 KiB
JavaScript
Executable File

"use strict";
/** @module helpers */
require('es6-shim');
/** @alias module:helpers */
var h = {
/**
* Wrap String.prototype.trim in a way that is easily mappable
*
* @param {String} str - The string to trim
* @return {String} - The trimmed string
*/
stringTrim: function(str) {
return str.trim();
},
/**
* Get the type of the variable passed
*
* @see https://techblog.badoo.com/blog/2013/11/01/type-checking-in-javascript/
* @see http://toddmotto.com/understanding-javascript-types-and-reliable-type-checking/
* @param {mixed} o
* @return {String}
*/
type: function (o) {
var type = Object.prototype.toString.call(o).slice(8, -1).toLowerCase();
// handle NaN and Infinity
if (type === 'number') {
if (isNaN(o)) {
return 'nan';
}
if (!isFinite(o)) {
return 'infinity';
}
}
return type;
},
/**
* Determine whether an object is scalar
*
* @param {mixed} obj
* @return {bool}
*/
isScalar: function(obj) {
var scalar = ['string', 'number', 'boolean'];
return scalar.indexOf(h.type(obj)) !== -1;
},
/**
* Get a list of values with a common key from an array of objects
*
* @param {Array} arr - The array of objects to search
* @param {String} key - The key of the object to get
* @return {Array}
*/
arrayPluck: function(arr, key) {
var output = [];
// Empty case
if (arr.length === 0) return output;
arr.forEach(function(obj) {
if ( ! h.isUndefined(obj[key]))
{
output.push(obj[key]);
}
});
return output;
},
/**
* Determine if a value matching the passed regular expression is
* in the passed array
*
* @param {Array} arr - The array to search
* @param {RegExp} pattern - The pattern to match
* @return {Boolean} - If an array item matches the pattern
*/
regexInArray: function(arr, pattern) {
// Empty case(s)
if ( ! h.isArray(arr)) return false;
if (arr.length === 0) return false;
var i, l = arr.length;
for(i=0; i< l; i++)
{
// Recurse for nested arrays
if (Array.isArray(arr[i]))
{
return h.regexInArray(arr[i], pattern);
}
// Short circuit if any items match
if (pattern.test(arr[i])) return true;
}
return false;
}
};
// Define an 'is' method for each type
var types = ['Null','Undefined','Object','Array','String','Number','Boolean','Function','RegExp','NaN','Infinite'];
types.forEach(function (t) {
/**
* Determine whether a variable is of the type specified in the
* function name, eg isNumber
*
* Types available are Null, Undefined, Object, Array, String, Number, Boolean, Function, RegExp, NaN and Infinite
*
* @name is[type]
* @param {mixed} o
* @return {Boolean}
*/
h['is' + t] = function (o) {
if (t.toLowerCase() === 'infinite')
{
t = 'infinity';
}
return h.type(o) === t.toLowerCase();
};
});
module.exports = h;