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pure ts module based programming example
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| // Your module (i.e. file is for providing and working with one main type) | |
| export type FooBar = { | |
| foo: string; | |
| bar: number; | |
| then: (fn: (foobar: FooBar) => FooBar) => FooBar; | |
| map: <T>(fn: (foobar: FooBar) => T) => T; | |
| }; | |
| function make({ foo = "", bar = 0 }: Readonly<{ foo?: string; bar?: number }>) { | |
| const foobar: FooBar = { | |
| foo, | |
| bar, | |
| then: function (fn: (fb: FooBar) => FooBar): FooBar { | |
| return fn(this); | |
| }, | |
| map: function <T>(fn: (fb: FooBar) => T): T { | |
| return fn(this); | |
| }, | |
| }; | |
| return foobar; | |
| } | |
| function upperCaseFoo({ foo, bar }: FooBar): FooBar { | |
| return make({ foo: foo.toUpperCase(), bar }); | |
| } | |
| function doubleBar({ foo, bar }: FooBar): FooBar { | |
| return make({ foo, bar: bar * 2 }); | |
| } | |
| function toToml(foobar: FooBar): string { | |
| return ` | |
| [foobar] | |
| foo = ${foobar.foo} | |
| bar = ${foobar.bar} | |
| `; | |
| } | |
| function then(foobar: FooBar, fn: (_: FooBar) => FooBar): FooBar { | |
| return fn(foobar); | |
| } | |
| function map<T>(foobar: FooBar, fn: (_: FooBar) => T): T { | |
| return fn(foobar); | |
| } | |
| // You export an object of functions to operate on that one type | |
| export const FooBar = { | |
| doubleBar, | |
| make, | |
| map, | |
| then, | |
| toToml, | |
| upperCaseFoo, | |
| } as const; |
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| import { FooBar } from "./foobar"; | |
| // We can use the export as a type and Module to operate on the type | |
| const foobar: FooBar = FooBar.make({ foo: "foo", bar: 10 }); | |
| const foobarToml = foobar | |
| .then(FooBar.doubleBar) | |
| .then(FooBar.upperCaseFoo) | |
| // we can also use our own functions in `then` or `map` | |
| .then(({ foo, bar }) => FooBar.make({ foo: `new foo + ${foo}`, bar })) | |
| .map(FooBar.toToml); | |
| console.log(foobarToml); | |
| // outputs: | |
| // [foobar] | |
| // foo = new foo + FOO | |
| // bar = 20 |
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