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63c5a28946
Removed unneeded parentheses from ```System.entries``` example, in order to work as expected.
102 lines
2.5 KiB
Markdown
102 lines
2.5 KiB
Markdown
## SystemJS API
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### Core API (s.js & system.js)
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#### System.constructor
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Type: `Function`
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This represents the System base class, which can be extended or reinstantiated to create a custom System instance.
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Example:
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```js
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var clonedSystem = new System.constructor();
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clonedSystem.import('x'); // imports in a custom context
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```
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#### System.import(id [, parentURL]) -> Promise(Module)
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Type: `Function`
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Loads a module by name taking an optional normalized parent URL argument.
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Promise resolves to the ES module namespace value.
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_Note: If provided, `parentURL` must be a valid URL, or URL resolution may break._
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#### System.register(deps, declare)
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Type: `Function`
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Declaration function for defining modules of the `System.register` polyfill module format.
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[Read more on the format at the loader polyfill page](system-register.md)
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_Note: Named System.register is not supported, only anonymous definitions._
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#### System.resolve(id [, parentURL]) -> Promise(string)
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Type: `Function`
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Resolves a module specifier relative to an optional parent URL, returning the resolved URL.
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### Registry API (system.js only)
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#### System.delete(id) -> Boolean
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Type: `Function`
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Deletes a module from the registry by ID.
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Returns true if the module was found in the registry before deletion.
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```js
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System.delete('http://site.com/normalized/module/name.js');
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```
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#### System.get(id) -> Module
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Type: `Function`
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Retrieve a loaded module from the registry by ID.
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```js
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System.get('http://site.com/normalized/module/name.js').exportedFunction();
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```
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Module records with an error state will return `null`.
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#### System.has(id) -> Boolean
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Type: `Function`
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Determine if a given ID is available in the loader registry.
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Module records that have an error state in the registry still return `true`,
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while module records with in-progress loads will return `false`.
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```js
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System.has('http://site.com/normalized/module/name.js');
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```
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#### System.set(id, module) -> Module
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Type: `Function`
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Sets a module in the registry by ID.
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```js
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System.set('http://site.com/normalized/module/name.js', {
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exportedFunction: value
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});
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```
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`module` is an object of names to set as the named exports.
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If `module` is an existing Module Namespace, it will be used by reference.
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#### System.entries() -> Iterator<[key, module]>
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Type: `Function`
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Allows you to retrieve all modules in the System registry. Each value will be an array with two values: a key and the module.
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```js
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for (const [id, ns] of System.entries()) {
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console.log(id); // 'http://localhost/path-to-file.js'
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console.log(ns); // { exportName: 'value' }
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};
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```
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