64 lines
956 B
Markdown
64 lines
956 B
Markdown
# babel-plugin-transform-remove-undefined
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For variable assignments, this removes rvals that evaluate to `undefined`
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(`var`s in functions only).
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For functions, this removes return arguments that evaluate to `undefined`.
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## Example
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**In**
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```javascript
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let a = void 0;
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function foo() {
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var b = undefined;
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return undefined;
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}
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```
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**Out**
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```javascript
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let a;
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function foo() {
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var b;
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return;
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}
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```
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## Installation
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```sh
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npm install babel-plugin-transform-remove-undefined
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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-transform-remove-undefined"]
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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-transform-remove-undefined 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-transform-remove-undefined"]
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});
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```
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## Options
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+ `tdz` - Detect usages before declaration/initialization in let/const(throws) and var(void 0)
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