x-query-string/encode.js

var util = require('./util/util');
var isArray = util.isArray;
var isObject = util.isObject;
var hasOwn = Object.prototype.hasOwnProperty;

/**
 * Encode the given object to URI Component encoded query string
 *
 * @param {Object.<string, *>} object The object to encode
 * @param {boolean} [keepArrayIndex] Whether to keep array index
 * @returns {string} Returns the URI Component encoded query string
 */
function encode(object, keepArrayIndex) {
    var key;
    var keyValueArray = [];

    keepArrayIndex = !!keepArrayIndex;

    if ( isObject(object) ) {
        for ( key in object ) {
            if ( hasOwn.call(object, key) ) {
                encodeKey(key, object[key], keyValueArray, keepArrayIndex);
            }
        }
    }

    return keyValueArray.join('&');
}

/**
 * Encode the speceifed key in the object
 *
 * @param {string} key The key name
 * @param {any} data The data of the key
 * @param {string[]} keyValueArray The array to store the key value string
 * @param {boolean} keepArrayIndex Whether to keep array index
 */
function encodeKey(key, data, keyValueArray, keepArrayIndex) {
    var prop;
    var index;
    var length;
    var value;
    var subKey;

    if ( isObject(data) ) {
        for ( prop in data ) {
            if ( hasOwn.call(data, prop) ) {
                value = data[prop];
                subKey = key + '[' + prop + ']';
                encodeKey(subKey, value, keyValueArray, keepArrayIndex);
            }
        }
    } else if ( isArray(data) ) {
        index = 0;
        length = data.length;

        while (index < length) {
            value = data[index];

            if ( keepArrayIndex || isArray(value) || isObject(value) ) {
                subKey = key + '[' + index + ']';
            } else {
                subKey = key + '[]';
            }

            encodeKey(subKey, value, keyValueArray, keepArrayIndex);

            index += 1;
        }
    } else {
        key = encodeURIComponent(key);
        // if data is null, no `=` is appended
        if (data === null) {
            value = key;
        } else {
            // if data is undefined, treat it as empty string
            if (data === undefined) {
                data = '';
            // make sure that data is string
            } else if (typeof data !== 'string') {
                data = '' + data;
            }
            value = key + '=' + encodeURIComponent(data);
        }

        keyValueArray.push(value);
    }
}

module.exports = encode;