make-synchronized
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# make-synchronized
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[package_link]: https://www.npmjs.com/package/make-synchronized
> Make synchronized functions.
## Install
```bash
yarn add make-synchronized
```
## Usage
This module mainly to support two kinds of different purpose of usage:
1. Make a module that turns asynchronous function into synchronized
```js
import makeSynchronized from 'make-synchronized'
export default makeSynchronized(import.meta, myAsynchronousFunction)
```
1. Make asynchronous functions in an existing module into synchronized
```js
import makeSynchronized from 'make-synchronized'
const synchronized = makeSynchronized(
new URL('./my-asynchronous-function-module.js', import.meta.url),
)
```
## Named exports
```js
import {
makeSynchronized, // Same as the default export
makeDefaultExportSynchronized,
makeModuleSynchronized,
makeSynchronizedFunction,
makeSynchronizedFunctions,
} from 'make-synchronized'
```
## Limitation
This module uses [`MessagePort#postMessage`](https://nodejs.org/api/worker_threads.html#portpostmessagevalue-transferlist) to transfer arguments, return values, errors between the main thread and the [worker](https://nodejs.org/api/worker_threads.html#class-worker). Please make sure the arguments and return values are serializable by [the structured clone algorithm](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm).
## API
### `makeSynchronized(module, implementation)`
> Make asynchronous functions to be synchronized for export.
- If `implementation` is a `function`, returns a synchronized version of the passed function.
**Note: It MUST be used as the default export**
```js
// foo.js
import makeSynchronized from 'make-synchronized'
export default makeSynchronized(import.meta, () => Promise.resolve('foo'))
```
```js
import foo from './foo.js'
foo()
// -> foo
```
- [Example](./examples/use-module-synchronized-as-default.js)
- If `implementation` is a `object` with multiple functions, returns a `Proxy` object with synchronized functions attached.
**Note: Functions MUST exported as the same name as the key in `implementation` object.**
```js
// foo-and-bar.js
import makeSynchronized from 'make-synchronized'
export const {foo, bar} = makeSynchronized(import.meta, {
async foo() {
return 'foo'
},
async bar() {
return 'bar'
},
})
```
```js
import {foo, bar} from './foo-and-bar.js'
foo()
// -> foo
bar()
// -> bar
```
- [Example](./examples/use-module-synchronized-as-default.js)
### `makeSynchronized(module)`
> Make asynchronous functions in an existing module to be synchronized to call.
- If the passing `module` is a module that contains a function type default export, returns a `Proxy` function, with other specifiers attached.
```js
// foo.js
export default () => Promise.resolve('default export called')
export const foo = 'foo'
export const bar = () => Promise.resolve('bar called')
```
```js
const synchronized = makeSynchronized(new URL('./foo.js', import.meta.url))
synchronized()
// -> "default export called"
synchronized.foo
// -> "foo"
// This function also synchronized.
synchronized.bar()
// -> "bar called"
```
[Example](./examples/make-default-export-function-synchronized.js)
- If the passing `module` is a module without default export or default export is not a function, a `Module` object will be returned with all specifiers.
```js
// foo.js
export const foo = 'foo'
export const bar = () => Promise.resolve('bar called')
```
```js
import makeSynchronized from 'make-synchronized'
const module = makeSynchronized(new URL('./foo.js', import.meta.url))
module
// [Object: null prototype] [Module] { bar: [Getter], foo: [Getter] }
module.foo
// -> "foo"
module.bar()
// -> "bar called"
```
[Example](./examples/make-module-specifiers-synchronized.js)
### `makeSynchronizedFunction(module, implementation, specifier?)`
> Make a synchronized function for export.
Explicit version of `makeSynchronized(module, implementation)` that returns the synchronized function for export.
```js
import {makeSynchronizedFunction} from 'make-synchronized'
export default makeSynchronizedFunction(
import.meta,
async () => 'default export called',
)
export const foo = makeSynchronizedFunction(
import.meta,
async () => 'foo export called',
'foo',
)
```
### `makeSynchronizedFunctions(module, implementation)`
> Make synchronized functions for export.
Explicit version of `makeSynchronized(module, implementation)` that only returns `Proxy` with synchronized functions for export.
```js
import {makeSynchronizedFunctions} from 'make-synchronized'
export const {
// MUST match the key in second argument
foo,
bar,
} = makeSynchronizedFunctions(import.meta, {
foo: async () => 'foo export called',
bar: async () => 'bar export called',
})
```
### `makeDefaultExportSynchronized(module)`
> Make an existing module's default export to be a synchronized function.
Explicit version of `makeSynchronized(module)` that only returns the synchronized default export.
```js
import {makeDefaultExportSynchronized} from 'make-synchronized'
const foo = makeModuleSynchronized('foo')
foo()
// -> default export of `foo` module is called.
```
### `makeModuleSynchronized(module)`
> Make an existing module's exports to be synchronized functions.
Synchronize version of `import(module)`, always returns a `Module`.
```diff
- const {default: foo} = await import('foo')
+ const {default: foo} = makeModuleSynchronized('foo')
```
```js
import {makeModuleSynchronized} from 'make-synchronized'
const {default: foo, bar} = makeModuleSynchronized('foo')
foo()
// -> default export of `foo` module is called.
bar()
// -> `bar` function from `foo` module is called.
```