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util: improve util.format performance

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By manually copying arguments and breaking the try/catch out, we are
able to improve the performance of util.format by 20-100% (depending on
the types).

PR-URL: https://github.com/nodejs/node/pull/5360
Reviewed-By: James M Snell <jasnell@gmail.com>
This commit is contained in:
Evan Lucas 2016-02-22 02:55:55 -06:00
parent 735e0df8e4
commit 8d72b0d291
1 changed files with 22 additions and 13 deletions
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35
lib/util.js
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@ -9,39 +9,48 @@ const isError = internalUtil.isError;
var Debug;
function tryStringify(arg) {
try {
return JSON.stringify(arg);
} catch (_) {
return '[Circular]';
}
}
const formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
if (typeof f !== 'string') {
var objects = [];
const objects = new Array(arguments.length);
for (var index = 0; index < arguments.length; index++) {
objects.push(inspect(arguments[index]));
objects[index] = inspect(arguments[index]);
}
return objects.join(' ');
}
if (arguments.length === 1) return f;
var i = 1;
var args = arguments;
var len = args.length;
var str = String(f).replace(formatRegExp, function(x) {
const len = arguments.length;
const args = new Array(len);
var i;
for (i = 0; i < len; i++) {
args[i] = arguments[i];
}
i = 1;
var str = f.replace(formatRegExp, function(x) {
if (x === '%%') return '%';
if (i >= len) return x;
switch (x) {
case '%s': return String(args[i++]);
case '%d': return Number(args[i++]);
case '%j':
try {
return JSON.stringify(args[i++]);
} catch (_) {
return '[Circular]';
}
case '%j': return tryStringify(args[i++]);
// falls through
default:
return x;
}
});
for (var x = args[i]; i < len; x = args[++i]) {
while (i < len) {
const x = args[i++];
if (x === null || (typeof x !== 'object' && typeof x !== 'symbol')) {
str += ' ' + x;
} else {