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119 lines
2.5 KiB
JavaScript

'use strict';
var has = Object.prototype.hasOwnProperty
, undef;
/**
* Decode a URI encoded string.
*
* @param {String} input The URI encoded string.
* @returns {String|Null} The decoded string.
* @api private
*/
function decode(input) {
try {
return decodeURIComponent(input.replace(/\+/g, ' '));
} catch (e) {
return null;
}
}
/**
* Attempts to encode a given input.
*
* @param {String} input The string that needs to be encoded.
* @returns {String|Null} The encoded string.
* @api private
*/
function encode(input) {
try {
return encodeURIComponent(input);
} catch (e) {
return null;
}
}
/**
* Simple query string parser.
*
* @param {String} query The query string that needs to be parsed.
* @returns {Object}
* @api public
*/
function querystring(query) {
var parser = /([^=?#&]+)=?([^&]*)/g
, result = {}
, part;
while (part = parser.exec(query)) {
var key = decode(part[1])
, value = decode(part[2]);
//
// Prevent overriding of existing properties. This ensures that build-in
// methods like `toString` or __proto__ are not overriden by malicious
// querystrings.
//
// In the case if failed decoding, we want to omit the key/value pairs
// from the result.
//
if (key === null || value === null || key in result) continue;
result[key] = value;
}
return result;
}
/**
* Transform a query string to an object.
*
* @param {Object} obj Object that should be transformed.
* @param {String} prefix Optional prefix.
* @returns {String}
* @api public
*/
function querystringify(obj, prefix) {
prefix = prefix || '';
var pairs = []
, value
, key;
//
// Optionally prefix with a '?' if needed
//
if ('string' !== typeof prefix) prefix = '?';
for (key in obj) {
if (has.call(obj, key)) {
value = obj[key];
//
// Edge cases where we actually want to encode the value to an empty
// string instead of the stringified value.
//
if (!value && (value === null || value === undef || isNaN(value))) {
value = '';
}
key = encode(key);
value = encode(value);
//
// If we failed to encode the strings, we should bail out as we don't
// want to add invalid strings to the query.
//
if (key === null || value === null) continue;
pairs.push(key +'='+ value);
}
}
return pairs.length ? prefix + pairs.join('&') : '';
}
//
// Expose the module.
//
exports.stringify = querystringify;
exports.parse = querystring;