All files throttle.ts

100% Statements 66/66
100% Branches 20/20
100% Functions 15/15
100% Lines 65/65

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 1961x                                                                     1x 76x     1x                                 1x 20x 20x 20x                       20x 1x     19x 19x 19x 86x   86x 82x   60x 60x 60x 60x     22x 22x 22x 22x 7x 7x   15x     4x 1x 1x 1x 1x   3x 3x           19x   80x 8x     72x 72x 10x   72x 12x   60x 26x       19x   91x 90x   86x   4x 4x 4x           19x 65x                       8x 8x   4x     4x 2x   2x                         1x 4x 4x                 1x 4x 4x    
const DEFAULT_MAX = 5;
 
export interface Result<T> {
    amountDone: number;
    amountStarted: number;
    amountResolved: number;
    amountRejected: number;
    amountNextCheckFalsey: number;
    rejectedIndexes: number[];
    resolvedIndexes: number[];
    nextCheckFalseyIndexes: number[];
    taskResults: T[];
}
 
export interface Options {
    maxInProgress?: number;
    failFast?: boolean;
    progressCallback?: <T>(result: Result<T>) => void;
    nextCheck?: nextTaskCheck;
    ignoreIsFunctionCheck?: boolean;
}
 
/**
 * Default checker which validates if a next task should begin.
 * This can be overwritten to write own checks for example checking the amount
 * of used ram and waiting till the ram is low enough for a next task.
 *
 * It should always resolve with a boolean, either `true` to start a next task
 * or `false` to stop executing a new task.
 *
 * If this method rejects, the error will propagate to the caller
 * @param status
 * @param tasks
 * @returns {Promise}
 */
const defaultNextTaskCheck: nextTaskCheck = async <T>(status: Result<T>, tasks: Tasks<T>): Promise<boolean> => {
    return Promise.resolve(status.amountStarted < tasks.length);
};
 
const DEFAULT_OPTIONS = {
    maxInProgress: DEFAULT_MAX,
    failFast: false,
    nextCheck: defaultNextTaskCheck,
    ignoreIsFunctionCheck: false
};
 
export type Task<T> = () => Promise<T>;
export type Tasks<T> = Array<Task<T>>;
export type nextTaskCheck = <T>(status: Result<T>, tasks: Tasks<T>) => Promise<boolean>;
 
/**
 * Raw throttle function, which can return extra meta data.
 * @param tasks required array of tasks to be executed
 * @param options Options object
 * @returns {Promise}
 */
export async function raw<T>(tasks: Tasks<T>, options?: Options): Promise<Result<T>> {
    return new Promise<Result<T>>((resolve, reject) => {
        const myOptions = Object.assign({}, DEFAULT_OPTIONS, options);
        const result: Result<T> = {
            amountDone: 0,
            amountStarted: 0,
            amountResolved: 0,
            amountRejected: 0,
            amountNextCheckFalsey: 0,
            rejectedIndexes: [],
            resolvedIndexes: [],
            nextCheckFalseyIndexes: [],
            taskResults: []
        };
 
        if (tasks.length === 0) {
            return resolve(result);
        }
 
        let failedFast = false;
        let currentTaskIndex = 0;
        const executeTask = (index: number) => {
            result.amountStarted++;
 
            if (typeof tasks[index] === 'function') {
                tasks[index]().then(
                    taskResult => {
                        result.taskResults[index] = taskResult;
                        result.resolvedIndexes.push(index);
                        result.amountResolved++;
                        taskDone();
                    },
                    error => {
                        result.taskResults[index] = error;
                        result.rejectedIndexes.push(index);
                        result.amountRejected++;
                        if (myOptions.failFast === true) {
                            failedFast = true;
                            return reject(result);
                        }
                        taskDone();
                    }
                );
            } else if (myOptions.ignoreIsFunctionCheck === true) {
                result.taskResults[index] = (tasks[index] as any) as T;
                result.resolvedIndexes.push(index);
                result.amountResolved++;
                taskDone();
            } else {
                failedFast = true;
                return reject(
                    new Error('tasks[' + index + ']: ' + tasks[index] + ', is supposed to be of type function')
                );
            }
        };
 
        const taskDone = () => {
            //make sure no more tasks are spawned when we failedFast
            if (failedFast === true) {
                return;
            }
 
            result.amountDone++;
            if (typeof (myOptions as Options).progressCallback === 'function') {
                (myOptions as any).progressCallback(result);
            }
            if (result.amountDone === tasks.length) {
                return resolve(result);
            }
            if (currentTaskIndex < tasks.length) {
                nextTask(currentTaskIndex++);
            }
        };
 
        const nextTask = (index: number) => {
            //check if we can execute the next task
            myOptions.nextCheck(result, tasks).then(canExecuteNextTask => {
                if (canExecuteNextTask === true) {
                    //execute it
                    executeTask(index);
                } else {
                    result.amountNextCheckFalsey++;
                    result.nextCheckFalseyIndexes.push(index);
                    taskDone();
                }
            }, reject);
        };
 
        //spawn the first X task
        for (let i = 0; i < Math.min(myOptions.maxInProgress, tasks.length); i++) {
            nextTask(currentTaskIndex++);
        }
    });
}
 
/**
 * Executes the raw function, but only return the task array
 * @param tasks 
 * @param options 
 * @returns {Promise}
 */
async function executeRaw<T>(tasks: Tasks<T>, options: Options): Promise<T[]> {
    return new Promise<T[]>((resolve, reject) => {
        raw(tasks, options).then(
            (result: Result<T>) => {
                resolve(result.taskResults);
            },
            (error: Error | Result<T>) => {
                if (error instanceof Error) {
                    reject(error);
                } else {
                    reject(error.taskResults[error.rejectedIndexes[0]]);
                }
            }
        );
    });
}
 
/**
 * Simply run all the promises after each other, so in synchronous manner
 * @param tasks required array of tasks to be executed
 * @param options Options object
 * @returns {Promise}
 */
export async function sync<T>(tasks: Tasks<T>, options?: Options): Promise<T[]> {
    const myOptions = Object.assign({}, {maxInProgress: 1, failFast: true}, options);
    return executeRaw(tasks, myOptions);
}
 
/**
 * Exposes the same behaviour as Promise.All(), but throttled!
 * @param tasks required array of tasks to be executed
 * @param options Options object
 * @returns {Promise}
 */
export async function all<T>(tasks: Tasks<T>, options?: Options): Promise<T[]> {
    const myOptions = Object.assign({}, {failFast: true}, options);
    return executeRaw(tasks, myOptions);
}