extra-array-view/index.mjs

An array view is a proxy to an underlying array.

class RawArrayView {
    constructor(x, i = 0, I = x.length) {
        this.base = x;
        this.begin = i;
        this.end = I;
    }
    [Symbol.iterator]() {
        return this.base.slice(this.begin, this.end)[Symbol.iterator]();
    }
    keys() {
        return this.base.slice(this.begin, this.end).keys();
    }
    values() {
        return this.base.slice(this.begin, this.end).values();
    }
    entries() {
        return this.base.slice(this.begin, this.end).entries();
    }
    index(i) {
        return i >= 0 ? Math.min(this.begin + i, this.end) : Math.max(this.begin, this.end + i);
    }
    indexRange(i = 0, I = this.length) {
        var i = i >= 0 ? Math.min(this.begin + i, this.end) : Math.max(this.begin, this.end + i);
        var I = I >= 0 ? Math.min(this.begin + I, this.end) : Math.max(this.begin, this.end + I);
        return [i, Math.max(i, I)];
    }
    get length() {
        return this.end - this.begin;
    }
    get(i) {
        if (i >= 0 && i < this.length)
            return this.base[this.begin + i];
    }
    at(i) {
        if (i >= -this.length && i < this.length)
            return this.base[this.index(i)];
    }
    set(i, v) {
        if (i >= 0 && i < this.length)
            this.base[this.begin + i] = v;
    }
    sort(fc) {
        var x = this.base.slice(this.begin, this.end);
        x.sort(fc);
        this.base.splice(this.begin, x.length, ...x);
    }
    slice(i = 0, I = this.length) {
        return this.base.slice(this.begin, this.end).slice(i, I);
    }
    find(ft, ths) {
        return this.base.slice(this.begin, this.end).find(ft, ths);
    }
    findIndex(ft, ths) {
        return this.base.slice(this.begin, this.end).findIndex(ft, ths);
    }
    includes(v, i = 0) {
        return this.base.slice(this.begin, this.end).includes(v, i);
    }
    indexOf(v, i = 0) {
        return this.base.slice(this.begin, this.end).indexOf(v, i);
    }
    lastIndexOf(v, i = this.length - 1) {
        return this.base.slice(this.begin, this.end).lastIndexOf(v, i);
    }
    forEach(fn, ths) {
        this.base.slice(this.begin, this.end).forEach(fn, ths);
    }
    some(ft, ths) {
        return this.base.slice(this.begin, this.end).some(ft, ths);
    }
    every(ft, ths) {
        return this.base.slice(this.begin, this.end).every(ft, ths);
    }
    map(fm, ths) {
        return this.base.slice(this.begin, this.end).map(fm, ths);
    }
    reduce(fr, init) {
        return this.base.slice(this.begin, this.end).reduce(fr, init);
    }
    reduceRight(fr, init) {
        return this.base.slice(this.begin, this.end).reduceRight(fr, init);
    }
    filter(ft, ths) {
        return this.base.slice(this.begin, this.end).filter(ft, ths);
    }
    flat(d = 1) {
        return this.base.slice(this.begin, this.end).flat(d);
    }
    flatMap(fm, ths) {
        return this.base.slice(this.begin, this.end).flatMap(fm, ths);
    }
    fill(v, i = 0, I = this.length) {
        var [i, I] = this.indexRange(i, I);
        this.base.fill(v, i, I);
    }
    push(...vs) {
        return this.length;
    }
    pop() {
        return undefined;
    }
    shift() {
        return undefined;
    }
    unshift(...vs) {
        return this.length;
    }
    copyWithin(j, i, I = this.length) {
        var x = this.base.slice(this.begin, this.end);
        x.copyWithin(j, i, I);
        this.base.splice(this.begin, x.length, ...x);
    }
    splice(i, n, ...vs) {
        return [];
    }
    concat(...xs) {
        return this.base.slice(this.begin, this.end).concat(...xs);
    }
    join(sep = ",") {
        return this.base.slice(this.begin, this.end).join(sep);
    }
    reverse() {
        var x = this.base.slice(this.begin, this.end);
        x.reverse();
        this.base.splice(this.begin, x.length, ...x);
    }
    toLocaleString() {
        return this.base.slice(this.begin, this.end).toLocaleString();
    }
    toString() {
        return this.base.slice(this.begin, this.end).toString();
    }
}
function fromArray(x, i = 0, I = x.length) {
    var y = new RawArrayView(x, i, I);
    return new Proxy(x, {
        get(_, k) {
            if (typeof k === "symbol" || !isFinite(k))
                return y[k];
            return y.get(Number(k));
        },
        set(_, k, v) {
            if (typeof k === "symbol" || !isFinite(k))
                return false;
            y.set(Number(k), v);
            return true;
        },
        ownKeys(x) {
            return Reflect.ownKeys(x);
        }
    });
}

export { fromArray as from, fromArray };