--- a/devtools/shared/sprintfjs/sprintf.js
+++ b/devtools/shared/sprintfjs/sprintf.js
@@ -66,108 +66,45 @@
 
         var cursor = 1, tree_length = parse_tree.length, arg, output = [], i, k, match, pad, pad_character, pad_length, is_positive = true, sign = ''
         for (i = 0; i < tree_length; i++) {
             // parse tree contains either substrings or match results (array)
             if (typeof parse_tree[i] === 'string') {
                 output[output.length] = parse_tree[i]
             } else  {
                 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)
+                if (match[1]) { // positional argument (explicit)
                     arg = argv[match[1]]
                 }
                 else { // positional argument (implicit)
                     arg = argv[cursor++]
                 }
 
-                if (re.not_type.test(match[8]) && re.not_primitive.test(match[8]) && get_type(arg) == 'function') {
-                    arg = arg()
-                }
-
-                if (re.numeric_arg.test(match[8]) && (get_type(arg) != 'number' && isNaN(arg))) {
-                    throw new TypeError(sprintf("[sprintf] expecting number but found %s", get_type(arg)))
-                }
-
-                if (re.number.test(match[8])) {
-                    is_positive = arg >= 0
-                }
-
                 switch (match[8]) {
                     case 'S':
                     case 's':
                         arg = String(arg)
                         arg = (match[7] ? arg.substring(0, match[7]) : arg)
                     break
-                    case 'b':
-                        arg = parseInt(arg, 10).toString(2)
-                    break
-                    case 'c':
-                        arg = String.fromCharCode(parseInt(arg, 10))
-                    break
                     case 'd':
                     case 'i':
+                        if ((get_type(arg) != 'number' && isNaN(arg))) {
+                            throw new TypeError(sprintf("[sprintf] expecting number but found %s", get_type(arg)))
+                        }
+                        is_positive = arg >= 0
                         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 't':
-                        arg = String(!!arg)
-                        arg = (match[7] ? arg.substring(0, match[7]) : arg)
-                    break
-                    case 'T':
-                        arg = get_type(arg)
-                        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()
+                        if (!is_positive || match[3]) {
+                            sign = is_positive ? '+' : '-'
+                            arg = arg.toString().replace(re.sign, '')
+                        }
                     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 = ''
-                    }
+                if (!match[6]) {
+                    output[output.length] = sign + arg;
+                } else {
                     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('')