85 lines
1.5 KiB
Markdown
85 lines
1.5 KiB
Markdown
# @babel/plugin-proposal-nullish-coalescing-operator
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> Replace `??` with an inline helper.
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## Example
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**In**
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```javascript
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var foo = object.foo ?? "default";
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```
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**Out**
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```javascript
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var _object$foo;
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var foo = (_object$foo = object.foo) !== null && _object$foo !== void 0 ? _object$foo : "default";
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```
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> **NOTE:** We cannot use `!= null` here because `document.all == null` and
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> `document.all` has been deemed not "nullish".
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## Installation
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```sh
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npm install --save-dev @babel/plugin-proposal-nullish-coalescing-operator
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```
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## Usage
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### Via `.babelrc` (Recommended)
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**.babelrc**
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```json
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{
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"plugins": ["@babel/plugin-proposal-nullish-coalescing-operator"]
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}
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```
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### Via CLI
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```sh
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babel --plugins @babel/plugin-proposal-nullish-coalescing-operator script.js
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```
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### Via Node API
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```javascript
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require("@babel/core").transform("code", {
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plugins: ["@babel/plugin-proposal-nullish-coalescing-operator"]
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});
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```
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## Options
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### `loose`
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`boolean`, defaults to `false`.
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When `true`, this transform will pretend `document.all` does not exist,
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and perform loose equality checks with `null` instead of strict equality checks
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against both `null` and `undefined`.
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#### Example
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**In**
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```javascript
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var foo = object.foo ?? "default";
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```
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**Out**
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```javascript
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var _object$foo;
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var foo = (_object$foo = object.foo) != null ? _object$foo : "default";
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```
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## References
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* [Proposal: Nullish Coalescing](https://github.com/tc39-transfer/proposal-nullish-coalescing)
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