cerxes/babel
3
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Flip default parameter template (#4515)

Browse Source 
* Flip default parameter template

YMMV, I saved ~10b on a 2kb library. Not noticeable at the small scale, by why not do it anyway?

I've (unscientifically) found that flipping the default parameter conditional yields better gzip results. I think this is due to the slightly longer string it can now repeatedly match:

```js
// old
var param = arguments.length <= 0 || void 0 === arguments[0] ? null : arguments[0]
--------------------------------------------------------------^

// new
var param = arguments.length > 1 && void 0 !== arguments[1] ? arguments[1] : null
------------------------------------------------------------------------^
```

Though it's entirely likely gzip will also choose up to the index of the arguments if you many default parameters at different indexes.

* Update tests
This commit is contained in:
Justin Ridgewell
2016-09-25 17:05:53 -04:00
committed by Logan Smyth
parent 08b45ca853
commit c2ed9de7fb
10 changed files with 31 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
packages/babel-plugin-transform-es2015-destructuring/test/fixtures/destructuring/default-precedence/expected.js vendored
View File

@@ -1,6 +1,6 @@
var f0 = function (a) {
var b = arguments.length <= 1 || arguments[1] === undefined ? a : arguments[1];
var c = arguments.length <= 2 || arguments[2] === undefined ? b : arguments[2];
var b = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : a;
var c = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : b;
return [a, b, c];
};
@@ -9,8 +9,8 @@ assert.deepEqual(f0(1), [1, 1, 1]);
var f1 = function (_ref) {
var a = _ref.a;
var b = arguments.length <= 1 || arguments[1] === undefined ? a : arguments[1];
var c = arguments.length <= 2 || arguments[2] === undefined ? b : arguments[2];
var b = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : a;
var c = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : b;
return [a, b, c];
};
@@ -19,10 +19,10 @@ assert.deepEqual(f1({ a: 1 }), [1, 1, 1]);
var f2 = function (_ref2) {
var a = _ref2.a;
var b = arguments.length <= 1 || arguments[1] === undefined ? a : arguments[1];
var c = arguments.length <= 2 || arguments[2] === undefined ? a : arguments[2];
var b = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : a;
var c = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : a;
return [a, b, c];
};
assert.deepEqual(f2({ a: 1 }), [1, 1, 1]);
assert.deepEqual(f2({ a: 1 }), [1, 1, 1]);