Jon Staab
72 lines
1.7 KiB
TypeScript
72 lines
1.7 KiB
TypeScript
import {last} from './Tools'
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export class Fluent<T> {
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constructor(readonly xs: T[]) {}
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static create() {
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return this.from([])
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}
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static from<T>(xs: Iterable<T>) {
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return new Fluent<T>(Array.from(xs))
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}
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clone<K extends Fluent<T>>(this: K, xs: T[]): K {
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return new (this.constructor as { new (xs: T[]): K })(xs)
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}
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valueOf = () => this.xs
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first = () => this.xs[0]
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nth = (i: number) => this.xs[i]
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last = () => last(this.xs)
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count = () => this.xs.length
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exists = () => this.xs.length > 0
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has = (v: T) => this.xs.includes(v)
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every = (f: (t: T) => boolean) => this.xs.every(f)
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some = (f: (t: T) => boolean) => this.xs.some(f)
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find = (f: (t: T) => boolean) => this.xs.find(f)
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uniq = () => this.clone(Array.from(new Set(this.xs)))
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slice = (a: number, b?: number) => this.clone(this.xs.slice(a, b))
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take = (n: number) => this.slice(0, n)
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drop = (n: number) => this.slice(n)
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filter = (f: (t: T) => boolean) => this.clone(this.xs.filter(f))
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reject = (f: (t: T) => boolean) => this.clone(this.xs.filter(t => !f(t)))
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keep = (xs: T[]) => this.filter(x => xs.includes(x))
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without = (xs: T[]) => this.reject(x => xs.includes(x))
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map = (f: (t: T) => T) => this.clone(this.xs.map(f))
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mapTo = <U>(f: (t: T) => U) => Fluent.from(this.xs.map(f))
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flatMap = <U>(f: (t: T) => U[]) => Fluent.from(this.xs.flatMap(f))
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forEach = (f: (t: T, i: number) => void) => this.xs.forEach(f)
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join = (s: string) => this.valueOf().join(s)
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set = (i: number, x: T) => this.clone([...this.xs.slice(0, i), x, ...this.xs.slice(i + 1)])
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concat = (xs: T[]) => this.clone(this.xs.concat(xs))
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append = (x: T) => this.concat([x])
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prepend = (x: T) => this.clone([x].concat(this.xs))
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}
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