sprintf.js
1 (function(window) { 2 var re = { 3 not_string: /[^s]/, 4 number: /[diefg]/, 5 json: /[j]/, 6 not_json: /[^j]/, 7 text: /^[^\x25]+/, 8 modulo: /^\x25{2}/, 9 placeholder: /^\x25(?:([1-9]\d*)\$|\(([^\)]+)\))?(\+)?(0|'[^$])?(-)?(\d+)?(?:\.(\d+))?([b-gijosuxX])/, 10 key: /^([a-z_][a-z_\d]*)/i, 11 key_access: /^\.([a-z_][a-z_\d]*)/i, 12 index_access: /^\[(\d+)\]/, 13 sign: /^[\+\-]/ 14 } 15 16 function sprintf() { 17 var key = arguments[0], cache = sprintf.cache 18 if (!(cache[key] && cache.hasOwnProperty(key))) { 19 cache[key] = sprintf.parse(key) 20 } 21 return sprintf.format.call(null, cache[key], arguments) 22 } 23 24 sprintf.format = function(parse_tree, argv) { 25 var cursor = 1, tree_length = parse_tree.length, node_type = "", arg, output = [], i, k, match, pad, pad_character, pad_length, is_positive = true, sign = "" 26 for (i = 0; i < tree_length; i++) { 27 node_type = get_type(parse_tree[i]) 28 if (node_type === "string") { 29 output[output.length] = parse_tree[i] 30 } 31 else if (node_type === "array") { 32 match = parse_tree[i] // convenience purposes only 33 if (match[2]) { // keyword argument 34 arg = argv[cursor] 35 for (k = 0; k < match[2].length; k++) { 36 if (!arg.hasOwnProperty(match[2][k])) { 37 throw new Error(sprintf("[sprintf] property '%s' does not exist", match[2][k])) 38 } 39 arg = arg[match[2][k]] 40 } 41 } 42 else if (match[1]) { // positional argument (explicit) 43 arg = argv[match[1]] 44 } 45 else { // positional argument (implicit) 46 arg = argv[cursor++] 47 } 48 49 if (get_type(arg) == "function") { 50 arg = arg() 51 } 52 53 if (re.not_string.test(match[8]) && re.not_json.test(match[8]) && (get_type(arg) != "number" && isNaN(arg))) { 54 throw new TypeError(sprintf("[sprintf] expecting number but found %s", get_type(arg))) 55 } 56 57 if (re.number.test(match[8])) { 58 is_positive = arg >= 0 59 } 60 61 switch (match[8]) { 62 case "b": 63 arg = arg.toString(2) 64 break 65 case "c": 66 arg = String.fromCharCode(arg) 67 break 68 case "d": 69 case "i": 70 arg = parseInt(arg, 10) 71 break 72 case "j": 73 arg = JSON.stringify(arg, null, match[6] ? parseInt(match[6]) : 0) 74 break 75 case "e": 76 arg = match[7] ? arg.toExponential(match[7]) : arg.toExponential() 77 break 78 case "f": 79 arg = match[7] ? parseFloat(arg).toFixed(match[7]) : parseFloat(arg) 80 break 81 case "g": 82 arg = match[7] ? parseFloat(arg).toPrecision(match[7]) : parseFloat(arg) 83 break 84 case "o": 85 arg = arg.toString(8) 86 break 87 case "s": 88 arg = ((arg = String(arg)) && match[7] ? arg.substring(0, match[7]) : arg) 89 break 90 case "u": 91 arg = arg >>> 0 92 break 93 case "x": 94 arg = arg.toString(16) 95 break 96 case "X": 97 arg = arg.toString(16).toUpperCase() 98 break 99 } 100 if (re.json.test(match[8])) { 101 output[output.length] = arg 102 } 103 else { 104 if (re.number.test(match[8]) && (!is_positive || match[3])) { 105 sign = is_positive ? "+" : "-" 106 arg = arg.toString().replace(re.sign, "") 107 } 108 else { 109 sign = "" 110 } 111 pad_character = match[4] ? match[4] === "0" ? "0" : match[4].charAt(1) : " " 112 pad_length = match[6] - (sign + arg).length 113 pad = match[6] ? (pad_length > 0 ? str_repeat(pad_character, pad_length) : "") : "" 114 output[output.length] = match[5] ? sign + arg + pad : (pad_character === "0" ? sign + pad + arg : pad + sign + arg) 115 } 116 } 117 } 118 return output.join("") 119 } 120 121 sprintf.cache = {} 122 123 sprintf.parse = function(fmt) { 124 var _fmt = fmt, match = [], parse_tree = [], arg_names = 0 125 while (_fmt) { 126 if ((match = re.text.exec(_fmt)) !== null) { 127 parse_tree[parse_tree.length] = match[0] 128 } 129 else if ((match = re.modulo.exec(_fmt)) !== null) { 130 parse_tree[parse_tree.length] = "%" 131 } 132 else if ((match = re.placeholder.exec(_fmt)) !== null) { 133 if (match[2]) { 134 arg_names |= 1 135 var field_list = [], replacement_field = match[2], field_match = [] 136 if ((field_match = re.key.exec(replacement_field)) !== null) { 137 field_list[field_list.length] = field_match[1] 138 while ((replacement_field = replacement_field.substring(field_match[0].length)) !== "") { 139 if ((field_match = re.key_access.exec(replacement_field)) !== null) { 140 field_list[field_list.length] = field_match[1] 141 } 142 else if ((field_match = re.index_access.exec(replacement_field)) !== null) { 143 field_list[field_list.length] = field_match[1] 144 } 145 else { 146 throw new SyntaxError("[sprintf] failed to parse named argument key") 147 } 148 } 149 } 150 else { 151 throw new SyntaxError("[sprintf] failed to parse named argument key") 152 } 153 match[2] = field_list 154 } 155 else { 156 arg_names |= 2 157 } 158 if (arg_names === 3) { 159 throw new Error("[sprintf] mixing positional and named placeholders is not (yet) supported") 160 } 161 parse_tree[parse_tree.length] = match 162 } 163 else { 164 throw new SyntaxError("[sprintf] unexpected placeholder") 165 } 166 _fmt = _fmt.substring(match[0].length) 167 } 168 return parse_tree 169 } 170 171 var vsprintf = function(fmt, argv, _argv) { 172 _argv = (argv || []).slice(0) 173 _argv.splice(0, 0, fmt) 174 return sprintf.apply(null, _argv) 175 } 176 177 /** 178 * helpers 179 */ 180 function get_type(variable) { 181 return Object.prototype.toString.call(variable).slice(8, -1).toLowerCase() 182 } 183 184 function str_repeat(input, multiplier) { 185 return Array(multiplier + 1).join(input) 186 } 187 188 /** 189 * export to either browser or node.js 190 */ 191 if (typeof exports !== "undefined") { 192 exports.sprintf = sprintf 193 exports.vsprintf = vsprintf 194 } 195 else { 196 window.sprintf = sprintf 197 window.vsprintf = vsprintf 198 199 if (typeof define === "function" && define.amd) { 200 define(function() { 201 return { 202 sprintf: sprintf, 203 vsprintf: vsprintf 204 } 205 }) 206 } 207 } 208 })(typeof window === "undefined" ? this : window);