@woosh/meep-engine/src/core/process/task/util/countTask.js

Pure JavaScript game engine. Fully featured and production ready.

import Task from "../Task.js";
import { TaskSignal } from "../TaskSignal.js";

/**
 *
 * @param {number|function(*):number} initial
 * @param {number|function(*):number} limit limit is excluded from the count, same as `for(;i < limit;)`
 * @param {function(index:int)} callback
 * @returns {Task}
 */
export function countTask(initial, limit, callback) {
    let initialValue = 0;
    let limitValue = 0;

    let i = initialValue;

    function cycle() {
        if (i >= limitValue) {
            return TaskSignal.EndSuccess;
        }
        callback(i);
        i++;

        return TaskSignal.Continue;
    }

    const initialType = typeof initial;
    const limitType = typeof limit;

    const name = "count (from " + ((initialType === 'number') ? initial : 'variable') + " to " + ((limitType === 'number') ? limit : 'variable') + ")";

    return new Task({
        name: name,
        initializer() {

            if (initialType === "number") {
                initialValue = initial;
            } else if (initialType === "function") {
                initialValue = initial();
            }

            if (limitType === "number") {
                limitValue = limit;
            } else if (limitType === "function") {
                limitValue = limit();
            }

            i = initialValue;
        },
        cycleFunction: cycle,
        computeProgress: function () {
            const span = limitValue - initialValue;

            if (span === 0) {
                return 0;
            }

            return (i - initialValue) / span;
        }
    });
}