b2b3d7944a
* for-of: IteratorClose spec compatibility. See #3: https://tc39.github.io/ecma262/#sec-iteratorclose * Update spec fixtures for for-of. * Fix IteratorClose case for remap-async-to-generator. * Fix IteratorClose case for async-generator-function test output. * Modify few tests according to iteratorClose fix. * Fix iteratorClose for helpers.slicedToArray also. * Update iteratorClose fixture for commonjs.
babel-plugin-transform-es2015-block-scoping
Compile ES2015 block scoping (const and let) to ES5
Examples
In
{
let a = 3
}
let a = 3
Out
{
var _a = 3;
}
var a = 3;
Installation
npm install --save-dev babel-plugin-transform-es2015-block-scoping
Usage
Via .babelrc (Recommended)
.babelrc
Without options:
{
"plugins": ["transform-es2015-block-scoping"]
}
With options:
{
"plugins": [
["transform-es2015-block-scoping", {
"throwIfClosureRequired": true
}]
]
}
Via CLI
babel --plugins transform-es2015-block-scoping script.js
Via Node API
require("babel-core").transform("code", {
plugins: ["transform-es2015-block-scoping"]
});
Options throwIfClosureRequired
In cases such as the following it's impossible to rewrite let/const without adding an additional function and closure while transforming:
for (let i = 0; i < 5; i++) {
setTimeout(() => console.log(i), 1);
}
In extremely performance-sensitive code, this can be undesirable. If "throwIfClosureRequired": true is set, Babel throws when transforming these patterns instead of automatically adding an additional function.