sprintf.js

/**
 * Copyright (c) 2007-2016, Alexandru Marasteanu <hello [at) alexei (dot] ro>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the name of this software nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without
 *   specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* eslint-disable */
/* globals window, exports, define */

(function(window) {
    'use strict'

    var re = {
        not_string: /[^s]/,
        not_bool: /[^t]/,
        not_type: /[^T]/,
        not_primitive: /[^v]/,
        number: /[diefg]/,
        numeric_arg: /bcdiefguxX/,
        json: /[j]/,
        not_json: /[^j]/,
        text: /^[^\x25]+/,
        modulo: /^\x25{2}/,
        placeholder: /^\x25(?:([1-9]\d*)\$|\(([^\)]+)\))?(\+)?(0|'[^$])?(-)?(\d+)?(?:\.(\d+))?([b-gijosStTuvxX])/,
        key: /^([a-z_][a-z_\d]*)/i,
        key_access: /^\.([a-z_][a-z_\d]*)/i,
        index_access: /^\[(\d+)\]/,
        sign: /^[\+\-]/
    }

    function sprintf() {
        var key = arguments[0], cache = sprintf.cache
        if (!(cache[key] && cache.hasOwnProperty(key))) {
            cache[key] = sprintf.parse(key)
        }
        return sprintf.format.call(null, cache[key], arguments)
    }

    sprintf.format = function(parse_tree, argv) {
        var cursor = 1, tree_length = parse_tree.length, node_type = '', arg, output = [], i, k, match, pad, pad_character, pad_length, is_positive = true, sign = ''
        for (i = 0; i < tree_length; i++) {
            node_type = typeof parse_tree[i]
            // The items of parse tree are either strings or results of a match() call.
            if (node_type === 'string') {
                // this is not a placeholder, this is just a string.
                output[output.length] = parse_tree[i]
            }
            else {
                // this is a placeholder, need to identify its type, options and replace
                // it with the appropriate argument.
                match = parse_tree[i] // convenience purposes only
                if (match[2]) { // keyword argument
                    arg = argv[cursor]
                    for (k = 0; k < match[2].length; k++) {
                        if (!arg.hasOwnProperty(match[2][k])) {
                            throw new Error(sprintf('[sprintf] property "%s" does not exist', match[2][k]))
                        }
                        arg = arg[match[2][k]]
                    }
                }
                else if (match[1]) { // positional argument (explicit)
                    arg = argv[match[1]]
                }
                else { // positional argument (implicit)
                    arg = argv[cursor++]
                }

                // The most commonly used placeholder in DevTools is the string (%S or %s).
                // We check it first to avoid unnecessary verifications.
                let hasPadding = match[6];
                let patternType = match[8];
                if (!hasPadding && (patternType === "S" || patternType === "s")) {
                    if (typeof arg === "function") {
                        arg = arg();
                    }
                    if (typeof arg !== "string") {
                        arg = String(arg);
                    }
                    output[output.length] = match[7] ? arg.substring(0, match[7]) : arg;
                    continue;
                }

                if (re.not_type.test(match[8]) && re.not_primitive.test(match[8]) && typeof arg == 'function') {
                    arg = arg()
                }

                if (re.numeric_arg.test(match[8]) && (typeof arg != 'number' && isNaN(arg))) {
                    throw new TypeError(sprintf("[sprintf] expecting number but found %s", typeof arg))
                }

                if (re.number.test(match[8])) {
                    is_positive = arg >= 0
                }

                switch (match[8]) {
                    case 'b':
                        arg = parseInt(arg, 10).toString(2)
                    break
                    case 'c':
                        arg = String.fromCharCode(parseInt(arg, 10))
                    break
                    case 'd':
                    case 'i':
                        arg = parseInt(arg, 10)
                    break
                    case 'j':
                        arg = JSON.stringify(arg, null, match[6] ? parseInt(match[6]) : 0)
                    break
                    case 'e':
                        arg = match[7] ? parseFloat(arg).toExponential(match[7]) : parseFloat(arg).toExponential()
                    break
                    case 'f':
                        arg = match[7] ? parseFloat(arg).toFixed(match[7]) : parseFloat(arg)
                    break
                    case 'g':
                        arg = match[7] ? parseFloat(arg).toPrecision(match[7]) : parseFloat(arg)
                    break
                    case 'o':
                        arg = arg.toString(8)
                    break
                    case 's':
                    case 'S':
                        arg = String(arg)
                        arg = (match[7] ? arg.substring(0, match[7]) : arg)
                    break
                    case 't':
                        arg = String(!!arg)
                        arg = (match[7] ? arg.substring(0, match[7]) : arg)
                    break
                    case 'T':
                        arg = Object.prototype.toString.call(arg).slice(8, -1).toLowerCase()
                        arg = (match[7] ? arg.substring(0, match[7]) : arg)
                    break
                    case 'u':
                        arg = parseInt(arg, 10) >>> 0
                    break
                    case 'v':
                        arg = arg.valueOf()
                        arg = (match[7] ? arg.substring(0, match[7]) : arg)
                    break
                    case 'x':
                        arg = parseInt(arg, 10).toString(16)
                    break
                    case 'X':
                        arg = parseInt(arg, 10).toString(16).toUpperCase()
                    break
                }
                if (re.json.test(match[8])) {
                    output[output.length] = arg
                }
                else {
                    if (re.number.test(match[8]) && (!is_positive || match[3])) {
                        sign = is_positive ? '+' : '-'
                        arg = arg.toString().replace(re.sign, '')
                    }
                    else {
                        sign = ''
                    }
                    pad_character = match[4] ? match[4] === '0' ? '0' : match[4].charAt(1) : ' '
                    pad_length = match[6] - (sign + arg).length
                    pad = match[6] ? (pad_length > 0 ? str_repeat(pad_character, pad_length) : '') : ''
                    output[output.length] = match[5] ? sign + arg + pad : (pad_character === '0' ? sign + pad + arg : pad + sign + arg)
                }
            }
        }
        return output.join('')
    }

    sprintf.cache = {}

    sprintf.parse = function(fmt) {
        var _fmt = fmt, match = [], parse_tree = [], arg_names = 0
        while (_fmt) {
            if ((match = re.text.exec(_fmt)) !== null) {
                parse_tree[parse_tree.length] = match[0]
            }
            else if ((match = re.modulo.exec(_fmt)) !== null) {
                parse_tree[parse_tree.length] = '%'
            }
            else if ((match = re.placeholder.exec(_fmt)) !== null) {
                if (match[2]) {
                    arg_names |= 1
                    var field_list = [], replacement_field = match[2], field_match = []
                    if ((field_match = re.key.exec(replacement_field)) !== null) {
                        field_list[field_list.length] = field_match[1]
                        while ((replacement_field = replacement_field.substring(field_match[0].length)) !== '') {
                            if ((field_match = re.key_access.exec(replacement_field)) !== null) {
                                field_list[field_list.length] = field_match[1]
                            }
                            else if ((field_match = re.index_access.exec(replacement_field)) !== null) {
                                field_list[field_list.length] = field_match[1]
                            }
                            else {
                                throw new SyntaxError("[sprintf] failed to parse named argument key")
                            }
                        }
                    }
                    else {
                        throw new SyntaxError("[sprintf] failed to parse named argument key")
                    }
                    match[2] = field_list
                }
                else {
                    arg_names |= 2
                }
                if (arg_names === 3) {
                    throw new Error("[sprintf] mixing positional and named placeholders is not (yet) supported")
                }
                parse_tree[parse_tree.length] = match
            }
            else {
                throw new SyntaxError("[sprintf] unexpected placeholder")
            }
            _fmt = _fmt.substring(match[0].length)
        }
        return parse_tree
    }

    var vsprintf = function(fmt, argv, _argv) {
        _argv = (argv || []).slice(0)
        _argv.splice(0, 0, fmt)
        return sprintf.apply(null, _argv)
    }

    /**
     * helpers
     */

    var preformattedPadding = {
        '0': ['', '0', '00', '000', '0000', '00000', '000000', '0000000'],
        ' ': ['', ' ', '  ', '   ', '    ', '     ', '      ', '       '],
        '_': ['', '_', '__', '___', '____', '_____', '______', '_______'],
    }
    function str_repeat(input, multiplier) {
        if (multiplier >= 0 && multiplier <= 7 && preformattedPadding[input]) {
            return preformattedPadding[input][multiplier]
        }
        return Array(multiplier + 1).join(input)
    }

    /**
     * export to either browser or node.js
     */
    if (typeof exports !== 'undefined') {
        exports.sprintf = sprintf
        exports.vsprintf = vsprintf
    }
    else {
        window.sprintf = sprintf
        window.vsprintf = vsprintf

        if (typeof define === 'function' && define.amd) {
            define(function() {
                return {
                    sprintf: sprintf,
                    vsprintf: vsprintf
                }
            })
        }
    }
})(typeof window === 'undefined' ? this : window);