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47 lines
1.4 KiB
Markdown
47 lines
1.4 KiB
Markdown
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# Notes about ES6 Class Syntax
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## Document Meta
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> **backend focus:** This documentation is more relevant to
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> Puter's backend than frontend, but is placed here because
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> it could apply to other areas in the future.
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## Expressions as Methods
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One important shortcoming in the ES6 class syntax to be aware of
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is that it discourages the use of expressions as methods.
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For example:
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```javascript
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class ExampleClass extends SomeBase {
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intuitive_method_definition () {}
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constructor () {
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this.less_intuitive = some_expr();
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}
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}
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```
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Even if it is known that the return type of `some_expr` is a function,
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it is still unclear whether it's being used as a callback or
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as a method without other context in the code, since this is
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how we typically assign instance members rather than methods.
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We solve this in Puter's backend using a **trait** called
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[AssignableMethodsTrait](../../packages/backend/src/traits/AssignableMethodsTrait.js)
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which allows a static member called `METHODS` to contain
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method definitions.
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### Uses for Expressions as Methods
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#### Method Composition
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Method Composition is the act of composing methods from other
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constituents. For example,
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[Sequence](../../packages/backend/src/codex/Sequence.js)
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allows composing a method from smaller functions, allowing
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easier definition of "in-betwewen-each" behaviors and ways
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to track which values from the arguments are actually read
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during a particular call.
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