解析url参数

parse.js

'use strict';

var has = Object.prototype.hasOwnProperty;

var hexTable = (function () {
    var array = [];
    for (var i = 0; i < 256; ++i) {
        array.push('%' + ((i < 16 ? '0' : '') + i.toString(16)).toUpperCase());
    }

    return array;
}());

var compactQueue = function compactQueue(queue) {
    while (queue.length > 1) {
        var item = queue.pop();
        var obj = item.obj[item.prop];

        if (Array.isArray(obj)) {
            var compacted = [];

            for (var j = 0; j < obj.length; ++j) {
                if (typeof obj[j] !== 'undefined') {
                    compacted.push(obj[j]);
                }
            }

            item.obj[item.prop] = compacted;
        }
    }
};

var arrayToObject = function arrayToObject(source, options) {
    var obj = options && options.plainObjects ? Object.create(null) : {};
    for (var i = 0; i < source.length; ++i) {
        if (typeof source[i] !== 'undefined') {
            obj[i] = source[i];
        }
    }

    return obj;
};

var merge = function merge(target, source, options) {
    if (!source) {
        return target;
    }

    if (typeof source !== 'object') {
        if (Array.isArray(target)) {
            target.push(source);
        } else if (typeof target === 'object') {
            if ((options && (options.plainObjects || options.allowPrototypes)) || !has.call(Object.prototype, source)) {
                target[source] = true;
            }
        } else {
            return [target, source];
        }

        return target;
    }

    if (typeof target !== 'object') {
        return [target].concat(source);
    }

    var mergeTarget = target;
    if (Array.isArray(target) && !Array.isArray(source)) {
        mergeTarget = arrayToObject(target, options);
    }

    if (Array.isArray(target) && Array.isArray(source)) {
        source.forEach(function (item, i) {
            if (has.call(target, i)) {
                if (target[i] && typeof target[i] === 'object' && item && typeof item === 'object') {
                    target[i] = merge(target[i], item, options);
                } else {
                    target.push(item);
                }
            } else {
                target[i] = item;
            }
        });
        return target;
    }

    return Object.keys(source).reduce(function (acc, key) {
        var value = source[key];

        if (has.call(acc, key)) {
            acc[key] = merge(acc[key], value, options);
        } else {
            acc[key] = value;
        }
        return acc;
    }, mergeTarget);
};

var assign = function assignSingleSource(target, source) {
    return Object.keys(source).reduce(function (acc, key) {
        acc[key] = source[key];
        return acc;
    }, target);
};

var decode = function (str, decoder, charset) {
    var strWithoutPlus = str.replace(/\+/g, ' ');
    if (charset === 'iso-8859-1') {
        // unescape never throws, no try...catch needed:
        return strWithoutPlus.replace(/%[0-9a-f]{2}/gi, unescape);
    }
    // utf-8
    try {
        return decodeURIComponent(strWithoutPlus);
    } catch (e) {
        return strWithoutPlus;
    }
};

var encode = function encode(str, defaultEncoder, charset) {
    // This code was originally written by Brian White (mscdex) for the io.js core querystring library.
    // It has been adapted here for stricter adherence to RFC 3986
    if (str.length === 0) {
        return str;
    }

    var string = typeof str === 'string' ? str : String(str);

    if (charset === 'iso-8859-1') {
        return escape(string).replace(/%u[0-9a-f]{4}/gi, function ($0) {
            return '%26%23' + parseInt($0.slice(2), 16) + '%3B';
        });
    }

    var out = '';
    for (var i = 0; i < string.length; ++i) {
        var c = string.charCodeAt(i);

        if (
            c === 0x2D // -
            || c === 0x2E // .
            || c === 0x5F // _
            || c === 0x7E // ~
            || (c >= 0x30 && c <= 0x39) // 0-9
            || (c >= 0x41 && c <= 0x5A) // a-z
            || (c >= 0x61 && c <= 0x7A) // A-Z
        ) {
            out += string.charAt(i);
            continue;
        }

        if (c < 0x80) {
            out = out + hexTable[c];
            continue;
        }

        if (c < 0x800) {
            out = out + (hexTable[0xC0 | (c >> 6)] + hexTable[0x80 | (c & 0x3F)]);
            continue;
        }

        if (c < 0xD800 || c >= 0xE000) {
            out = out + (hexTable[0xE0 | (c >> 12)] + hexTable[0x80 | ((c >> 6) & 0x3F)] + hexTable[0x80 | (c & 0x3F)]);
            continue;
        }

        i += 1;
        c = 0x10000 + (((c & 0x3FF) << 10) | (string.charCodeAt(i) & 0x3FF));
        out += hexTable[0xF0 | (c >> 18)]
            + hexTable[0x80 | ((c >> 12) & 0x3F)]
            + hexTable[0x80 | ((c >> 6) & 0x3F)]
            + hexTable[0x80 | (c & 0x3F)];
    }

    return out;
};

var compact = function compact(value) {
    var queue = [{ obj: { o: value }, prop: 'o' }];
    var refs = [];

    for (var i = 0; i < queue.length; ++i) {
        var item = queue[i];
        var obj = item.obj[item.prop];

        var keys = Object.keys(obj);
        for (var j = 0; j < keys.length; ++j) {
            var key = keys[j];
            var val = obj[key];
            if (typeof val === 'object' && val !== null && refs.indexOf(val) === -1) {
                queue.push({ obj: obj, prop: key });
                refs.push(val);
            }
        }
    }

    compactQueue(queue);

    return value;
};

var isRegExp = function isRegExp(obj) {
    return Object.prototype.toString.call(obj) === '[object RegExp]';
};

var isBuffer = function isBuffer(obj) {
    if (obj === null || typeof obj === 'undefined') {
        return false;
    }

    return !!(obj.constructor && obj.constructor.isBuffer && obj.constructor.isBuffer(obj));
};

var combine = function combine(a, b) {
    return [].concat(a, b);
};

var utils = {
    arrayToObject: arrayToObject,
    assign: assign,
    combine: combine,
    compact: compact,
    decode: decode,
    encode: encode,
    isBuffer: isBuffer,
    isRegExp: isRegExp,
    merge: merge
};


var defaults = {
    allowDots: false,
    allowPrototypes: false,
    arrayLimit: 20,
    charset: 'utf-8',
    charsetSentinel: false,
    decoder: utils.decode,
    delimiter: '&',
    depth: 5,
    ignoreQueryPrefix: false,
    interpretNumericEntities: false,
    parameterLimit: 1000,
    parseArrays: true,
    plainObjects: false,
    strictNullHandling: false
};

var interpretNumericEntities = function (str) {
    return str.replace(/&#(\d+);/g, function ($0, numberStr) {
        return String.fromCharCode(parseInt(numberStr, 10));
    });
};

// This is what browsers will submit when the ✓ character occurs in an
// application/x-www-form-urlencoded body and the encoding of the page containing
// the form is iso-8859-1, or when the submitted form has an accept-charset
// attribute of iso-8859-1. Presumably also with other charsets that do not contain
// the ✓ character, such as us-ascii.
var isoSentinel = 'utf8=%26%2310003%3B'; // encodeURIComponent('&#10003;')

// These are the percent-encoded utf-8 octets representing a checkmark, indicating that the request actually is utf-8 encoded.
var charsetSentinel = 'utf8=%E2%9C%93'; // encodeURIComponent('✓')

var parseValues = function parseQueryStringValues(str, options) {
    var obj = {};
    var cleanStr = options.ignoreQueryPrefix ? str.replace(/^\?/, '') : str;
    var limit = options.parameterLimit === Infinity ? undefined : options.parameterLimit;
    var parts = cleanStr.split(options.delimiter, limit);
    var skipIndex = -1; // Keep track of where the utf8 sentinel was found
    var i;

    var charset = options.charset;
    if (options.charsetSentinel) {
        for (i = 0; i < parts.length; ++i) {
            if (parts[i].indexOf('utf8=') === 0) {
                if (parts[i] === charsetSentinel) {
                    charset = 'utf-8';
                } else if (parts[i] === isoSentinel) {
                    charset = 'iso-8859-1';
                }
                skipIndex = i;
                i = parts.length; // The eslint settings do not allow break;
            }
        }
    }

    for (i = 0; i < parts.length; ++i) {
        if (i === skipIndex) {
            continue;
        }
        var part = parts[i];

        var bracketEqualsPos = part.indexOf(']=');
        var pos = bracketEqualsPos === -1 ? part.indexOf('=') : bracketEqualsPos + 1;

        var key, val;
        if (pos === -1) {
            key = options.decoder(part, defaults.decoder, charset);
            val = options.strictNullHandling ? null : '';
        } else {
            key = options.decoder(part.slice(0, pos), defaults.decoder, charset);
            val = options.decoder(part.slice(pos + 1), defaults.decoder, charset);
        }

        if (val && options.interpretNumericEntities && charset === 'iso-8859-1') {
            val = interpretNumericEntities(val);
        }
        if (has.call(obj, key)) {
            obj[key] = utils.combine(obj[key], val);
        } else {
            obj[key] = val;
        }
    }

    return obj;
};

var parseObject = function (chain, val, options) {
    var leaf = val;

    for (var i = chain.length - 1; i >= 0; --i) {
        var obj;
        var root = chain[i];

        if (root === '[]' && options.parseArrays) {
            obj = [].concat(leaf);
        } else {
            obj = options.plainObjects ? Object.create(null) : {};
            var cleanRoot = root.charAt(0) === '[' && root.charAt(root.length - 1) === ']' ? root.slice(1, -1) : root;
            var index = parseInt(cleanRoot, 10);
            if (!options.parseArrays && cleanRoot === '') {
                obj = { 0: leaf };
            } else if (
                !isNaN(index)
                && root !== cleanRoot
                && String(index) === cleanRoot
                && index >= 0
                && (options.parseArrays && index <= options.arrayLimit)
            ) {
                obj = [];
                obj[index] = leaf;
            } else {
                obj[cleanRoot] = leaf;
            }
        }

        leaf = obj;
    }

    return leaf;
};

var parseKeys = function parseQueryStringKeys(givenKey, val, options) {
    if (!givenKey) {
        return;
    }

    // Transform dot notation to bracket notation
    var key = options.allowDots ? givenKey.replace(/\.([^.[]+)/g, '[$1]') : givenKey;

    // The regex chunks

    var brackets = /(\[[^[\]]*])/;
    var child = /(\[[^[\]]*])/g;

    // Get the parent

    var segment = brackets.exec(key);
    var parent = segment ? key.slice(0, segment.index) : key;

    // Stash the parent if it exists

    var keys = [];
    if (parent) {
        // If we aren't using plain objects, optionally prefix keys that would overwrite object prototype properties
        if (!options.plainObjects && has.call(Object.prototype, parent)) {
            if (!options.allowPrototypes) {
                return;
            }
        }

        keys.push(parent);
    }

    // Loop through children appending to the array until we hit depth

    var i = 0;
    while ((segment = child.exec(key)) !== null && i < options.depth) {
        i += 1;
        if (!options.plainObjects && has.call(Object.prototype, segment[1].slice(1, -1))) {
            if (!options.allowPrototypes) {
                return;
            }
        }
        keys.push(segment[1]);
    }

    // If there's a remainder, just add whatever is left

    if (segment) {
        keys.push('[' + key.slice(segment.index) + ']');
    }

    return parseObject(keys, val, options);
};

var parse=function (str, opts) {
    var options = opts ? utils.assign({}, opts) : {};

    if (options.decoder !== null && options.decoder !== undefined && typeof options.decoder !== 'function') {
        throw new TypeError('Decoder has to be a function.');
    }

    options.ignoreQueryPrefix = options.ignoreQueryPrefix === true;
    options.delimiter = typeof options.delimiter === 'string' || utils.isRegExp(options.delimiter) ? options.delimiter : defaults.delimiter;
    options.depth = typeof options.depth === 'number' ? options.depth : defaults.depth;
    options.arrayLimit = typeof options.arrayLimit === 'number' ? options.arrayLimit : defaults.arrayLimit;
    options.parseArrays = options.parseArrays !== false;
    options.decoder = typeof options.decoder === 'function' ? options.decoder : defaults.decoder;
    options.allowDots = typeof options.allowDots === 'undefined' ? defaults.allowDots : !!options.allowDots;
    options.plainObjects = typeof options.plainObjects === 'boolean' ? options.plainObjects : defaults.plainObjects;
    options.allowPrototypes = typeof options.allowPrototypes === 'boolean' ? options.allowPrototypes : defaults.allowPrototypes;
    options.parameterLimit = typeof options.parameterLimit === 'number' ? options.parameterLimit : defaults.parameterLimit;
    options.strictNullHandling = typeof options.strictNullHandling === 'boolean' ? options.strictNullHandling : defaults.strictNullHandling;

    if (typeof options.charset !== 'undefined' && options.charset !== 'utf-8' && options.charset !== 'iso-8859-1') {
        throw new Error('The charset option must be either utf-8, iso-8859-1, or undefined');
    }
    if (typeof options.charset === 'undefined') {
        options.charset = defaults.charset;
    }

    if (str === '' || str === null || typeof str === 'undefined') {
        return options.plainObjects ? Object.create(null) : {};
    }

    var tempObj = typeof str === 'string' ? parseValues(str, options) : str;
    var obj = options.plainObjects ? Object.create(null) : {};

    // Iterate over the keys and setup the new object

    var keys = Object.keys(tempObj);
    for (var i = 0; i < keys.length; ++i) {
        var key = keys[i];
        var newObj = parseKeys(key, tempObj[key], options);
        obj = utils.merge(obj, newObj, options);
    }

    return utils.compact(obj);
};