fast-check/lib/esm/check/arbitrary/SubarrayArbitrary.js

Property based testing framework for JavaScript (like QuickCheck)

import { Stream } from '../../stream/Stream.js';
import { Arbitrary } from './definition/Arbitrary.js';
import { biasWrapper } from './definition/BiasedArbitraryWrapper.js';
import { Shrinkable } from './definition/Shrinkable.js';
import { integer } from './IntegerArbitrary.js';
import { makeLazy } from '../../stream/LazyIterableIterator.js';
class SubarrayArbitrary extends Arbitrary {
    constructor(originalArray, isOrdered, minLength, maxLength) {
        super();
        this.originalArray = originalArray;
        this.isOrdered = isOrdered;
        this.minLength = minLength;
        this.maxLength = maxLength;
        if (minLength < 0 || minLength > originalArray.length)
            throw new Error('fc.*{s|S}ubarrayOf expects the minimal length to be between 0 and the size of the original array');
        if (maxLength < 0 || maxLength > originalArray.length)
            throw new Error('fc.*{s|S}ubarrayOf expects the maximal length to be between 0 and the size of the original array');
        if (minLength > maxLength)
            throw new Error('fc.*{s|S}ubarrayOf expects the minimal length to be inferior or equal to the maximal length');
        this.lengthArb = integer(minLength, maxLength);
    }
    wrapper(items, shrunkOnce) {
        return new Shrinkable(items, () => this.shrinkImpl(items, shrunkOnce).map((v) => this.wrapper(v, true)));
    }
    generate(mrng) {
        const remainingElements = this.originalArray.map((v, idx) => idx);
        const size = this.lengthArb.generate(mrng).value;
        const ids = [];
        for (let idx = 0; idx !== size; ++idx) {
            const selectedIdIndex = mrng.nextInt(0, remainingElements.length - 1);
            ids.push(remainingElements[selectedIdIndex]);
            remainingElements.splice(selectedIdIndex, 1);
        }
        if (this.isOrdered)
            ids.sort((a, b) => a - b);
        return this.wrapper(ids.map((i) => this.originalArray[i]), false);
    }
    shrinkImpl(items, shrunkOnce) {
        if (items.length === 0) {
            return Stream.nil();
        }
        const size = this.lengthArb.shrinkableFor(items.length, shrunkOnce);
        return size
            .shrink()
            .map((l) => items.slice(items.length - l.value))
            .join(items.length > this.minLength
            ? makeLazy(() => this.shrinkImpl(items.slice(1), false)
                .filter((vs) => this.minLength <= vs.length + 1)
                .map((vs) => [items[0]].concat(vs)))
            : Stream.nil());
    }
    withBias(freq) {
        return this.minLength !== this.maxLength
            ? biasWrapper(freq, this, (originalArbitrary) => {
                return new SubarrayArbitrary(originalArbitrary.originalArray, originalArbitrary.isOrdered, originalArbitrary.minLength, originalArbitrary.minLength +
                    Math.floor(Math.log(originalArbitrary.maxLength - originalArbitrary.minLength) / Math.log(2)));
            })
            : this;
    }
}
function subarray(originalArray, minLength, maxLength) {
    if (minLength != null && maxLength != null)
        return new SubarrayArbitrary(originalArray, true, minLength, maxLength);
    return new SubarrayArbitrary(originalArray, true, 0, originalArray.length);
}
function shuffledSubarray(originalArray, minLength, maxLength) {
    if (minLength != null && maxLength != null)
        return new SubarrayArbitrary(originalArray, false, minLength, maxLength);
    return new SubarrayArbitrary(originalArray, false, 0, originalArray.length);
}
export { subarray, shuffledSubarray };