mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-23 06:10:02 +08:00
Chris Tate
022ac6eba9
Arrays whose elements are class-backed interface values are native arrays of the element capsules, so iteration, indexing and most array methods no longer go through the checked-dynamic array, and method calls receive a receiver they can dispatch. Methods without a native form for these elements run on the array's live dynamic view. A read of an interface property signature has the property's static type and reads the field of an implementing class directly. Accessors, object literals and JavaScript classes keep the checked property read.
77 lines
2.8 KiB
TypeScript
77 lines
2.8 KiB
TypeScript
// Array methods on arrays of interface values: searches compare element
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// identity, sorting and splicing move the same objects, copies share
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// elements with the source, and iterator methods yield the elements.
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interface Shape {
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area(): number;
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name(): string;
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}
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class Circle implements Shape {
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r: number;
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constructor(r: number) {
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this.r = r;
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}
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area(): number {
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return 3 * this.r * this.r;
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}
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name(): string {
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return `c${this.r}`;
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}
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}
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class Square implements Shape {
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side: number;
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constructor(side: number) {
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this.side = side;
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}
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area(): number {
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return this.side * this.side;
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}
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name(): string {
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return `s${this.side}`;
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}
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}
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const literal: Shape = { area: () => 50, name: () => "lit" };
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const a = new Circle(1);
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const b = new Square(3);
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const shapes: Shape[] = [a, b, literal, new Circle(2)];
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const names = (list: Shape[]): string => list.map((s) => s.name()).join(" ");
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console.log(shapes.indexOf(b), shapes.indexOf(new Square(3)), shapes.lastIndexOf(a));
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console.log(shapes.includes(literal), shapes.includes(new Circle(1)));
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const found = shapes.find((s) => s.area() > 10);
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console.log(found === undefined ? "none" : found.name(), shapes.findIndex((s) => s === literal));
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console.log(shapes.findLastIndex((s) => s.area() < 20));
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console.log(shapes.filter((s) => s.area() < 20).map((s) => s.name()).join(","));
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console.log(shapes.some((s) => s === b), shapes.every((s) => s.area() > 1));
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console.log(shapes.reduce((sum, s) => sum + s.area(), 0), shapes.reduceRight((acc, s) => acc + s.name(), ""));
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const last = shapes.at(-1);
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console.log(last === undefined ? "none" : last.name());
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const sorted = shapes.toSorted((x, y) => x.area() - y.area());
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console.log(names(sorted), names(shapes), sorted[0] === a);
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shapes.sort((x, y) => y.area() - x.area());
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console.log(names(shapes));
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console.log(names(shapes.toReversed()), names(shapes.slice(1, 3)));
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console.log(names(shapes.with(0, literal)), names(shapes.toSpliced(1, 2)));
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const removed = shapes.splice(1, 1, new Square(7), new Square(8));
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console.log(names(removed), names(shapes));
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console.log(names(shapes.concat([a], [literal])));
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shapes.reverse();
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const shifted = shapes.shift();
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const popped = shapes.pop();
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console.log(names(shapes), shifted === undefined ? "none" : shifted.name(), popped === undefined ? "none" : popped.name());
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shapes.unshift(b);
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console.log(names(shapes), shapes.length);
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console.log(shapes.flatMap((s) => [s.name(), s.area()]).join("|"));
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for (const [i, s] of shapes.entries()) console.log(i, s.name());
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for (const s of shapes.values()) console.log(s.area());
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console.log([...shapes.keys()].join(","));
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const copy = [...shapes, literal];
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const [head, ...rest] = copy;
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console.log(head === shapes[0], rest.length, names(copy));
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shapes.fill(literal, 1, 2);
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shapes.copyWithin(0, 2);
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console.log(names(shapes));
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