From 6b6488be27a71d9dba0ae5959284ae9a18ae9230 Mon Sep 17 00:00:00 2001
From: Sam Wilkins <samwilkins333@gmail.com>
Date: Thu, 19 Sep 2019 14:13:59 -0400
Subject: extensions fixes and tracking albums

---
 src/extensions/ArrayExtensions.ts | 341 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 341 insertions(+)
 create mode 100644 src/extensions/ArrayExtensions.ts

(limited to 'src/extensions/ArrayExtensions.ts')

diff --git a/src/extensions/ArrayExtensions.ts b/src/extensions/ArrayExtensions.ts
new file mode 100644
index 000000000..1190aa48c
--- /dev/null
+++ b/src/extensions/ArrayExtensions.ts
@@ -0,0 +1,341 @@
+interface BatchContext {
+    completedBatches: number;
+    remainingBatches: number;
+}
+type BatchConverterSync<I, O> = (batch: I[], context: BatchContext) => O[];
+type BatchHandlerSync<I> = (batch: I[], context: BatchContext) => void;
+type BatchConverterAsync<I, O> = (batch: I[], context: BatchContext) => Promise<O[]>;
+type BatchHandlerAsync<I> = (batch: I[], context: BatchContext) => Promise<void>;
+type BatchConverter<I, O> = BatchConverterSync<I, O> | BatchConverterAsync<I, O>;
+type BatchHandler<I> = BatchHandlerSync<I> | BatchHandlerAsync<I>;
+type FixedBatcher = { batchSize: number } | { batchCount: number, mode?: Mode };
+interface ExecutorResult<A> {
+    updated: A;
+    makeNextBatch: boolean;
+}
+interface PredicateBatcher<I, A> {
+    executor: (element: I, accumulator: A) => ExecutorResult<A>;
+    initial: A;
+    persistAccumulator?: boolean;
+}
+interface PredicateBatcherAsyncInterface<I, A> {
+    executor: (element: I, accumulator: A) => Promise<ExecutorResult<A>>;
+    initial: A;
+    persistAccumulator?: boolean;
+}
+type PredicateBatcherAsync<I, A> = PredicateBatcher<I, A> | PredicateBatcherAsyncInterface<I, A>;
+type Batcher<I, A> = FixedBatcher | PredicateBatcher<I, A>;
+type BatcherAsync<I, A> = Batcher<I, A> | PredicateBatcherAsync<I, A>;
+
+enum TimeUnit {
+    Milliseconds,
+    Seconds,
+    Minutes
+}
+
+interface Interval {
+    magnitude: number;
+    unit: TimeUnit;
+}
+
+enum Mode {
+    Balanced,
+    Even
+}
+
+const convert = (interval: Interval) => {
+    const { magnitude, unit } = interval;
+    switch (unit) {
+        default:
+        case TimeUnit.Milliseconds:
+            return magnitude;
+        case TimeUnit.Seconds:
+            return magnitude * 1000;
+        case TimeUnit.Minutes:
+            return magnitude * 1000 * 60;
+    }
+};
+
+interface Array<T> {
+    fixedBatch<T>(batcher: FixedBatcher): T[][];
+    predicateBatch<T, A = undefined>(batcher: PredicateBatcher<T, A>): T[][];
+    predicateBatchAsync<T, A = undefined>(batcher: PredicateBatcherAsync<T, A>): Promise<T[][]>;
+    batch<A = undefined>(batcher: Batcher<T, A>): T[][];
+    batchAsync<A = undefined>(batcher: BatcherAsync<T, A>): Promise<T[][]>;
+
+    batchedForEach<A = undefined>(batcher: Batcher<T, A>, handler: BatchHandlerSync<T>): void;
+    batchedMap<O, A = undefined>(batcher: Batcher<T, A>, handler: BatchConverterSync<T, O>): O[];
+
+    batchedForEachAsync<A = undefined>(batcher: Batcher<T, A>, handler: BatchHandler<T>): Promise<void>;
+    batchedMapAsync<O, A = undefined>(batcher: Batcher<T, A>, handler: BatchConverter<T, O>): Promise<O[]>;
+
+    batchedForEachInterval<A = undefined>(batcher: Batcher<T, A>, handler: BatchHandler<T>, interval: Interval): Promise<void>;
+    batchedMapInterval<O, A = undefined>(batcher: Batcher<T, A>, handler: BatchConverter<T, O>, interval: Interval): Promise<O[]>;
+
+    lastElement(): T;
+}
+
+module.exports.AssignArrayExtensions = function () {
+    Array.prototype.fixedBatch = module.exports.fixedBatch;
+    Array.prototype.predicateBatch = module.exports.predicateBatch;
+    Array.prototype.predicateBatchAsync = module.exports.predicateBatchAsync;
+    Array.prototype.batch = module.exports.batch;
+    Array.prototype.batchAsync = module.exports.batchAsync;
+    Array.prototype.batchedForEach = module.exports.batchedForEach;
+    Array.prototype.batchedMap = module.exports.batchedMap;
+    Array.prototype.batchedForEachAsync = module.exports.batchedForEachAsync;
+    Array.prototype.batchedMapAsync = module.exports.batchedMapAsync;
+    Array.prototype.batchedForEachInterval = module.exports.batchedForEachInterval;
+    Array.prototype.batchedMapInterval = module.exports.batchedMapInterval;
+    Array.prototype.lastElement = module.exports.lastElement;
+};
+
+module.exports.fixedBatch = function <T>(batcher: FixedBatcher): T[][] {
+    const batches: T[][] = [];
+    const length = this.length;
+    let i = 0;
+    if ("batchSize" in batcher) {
+        const { batchSize } = batcher;
+        while (i < this.length) {
+            const cap = Math.min(i + batchSize, length);
+            batches.push(this.slice(i, i = cap));
+        }
+    } else if ("batchCount" in batcher) {
+        let { batchCount, mode } = batcher;
+        const resolved = mode || Mode.Balanced;
+        if (batchCount < 1) {
+            throw new Error("Batch count must be a positive integer!");
+        }
+        if (batchCount === 1) {
+            return [this];
+        }
+        if (batchCount >= this.length) {
+            return this.map((element: T) => [element]);
+        }
+
+        let length = this.length;
+        let size: number;
+
+        if (length % batchCount === 0) {
+            size = Math.floor(length / batchCount);
+            while (i < length) {
+                batches.push(this.slice(i, i += size));
+            }
+        } else if (resolved === Mode.Balanced) {
+            while (i < length) {
+                size = Math.ceil((length - i) / batchCount--);
+                batches.push(this.slice(i, i += size));
+            }
+        } else {
+            batchCount--;
+            size = Math.floor(length / batchCount);
+            if (length % size === 0) {
+                size--;
+            }
+            while (i < size * batchCount) {
+                batches.push(this.slice(i, i += size));
+            }
+            batches.push(this.slice(size * batchCount));
+        }
+    }
+    return batches;
+};
+
+module.exports.predicateBatch = function <T, A>(batcher: PredicateBatcher<T, A>): T[][] {
+    const batches: T[][] = [];
+    let batch: T[] = [];
+    const { executor, initial, persistAccumulator } = batcher;
+    let accumulator = initial;
+    for (let element of this) {
+        const { updated, makeNextBatch } = executor(element, accumulator);
+        accumulator = updated;
+        if (!makeNextBatch) {
+            batch.push(element);
+        } else {
+            batches.push(batch);
+            batch = [element];
+            if (!persistAccumulator) {
+                accumulator = initial;
+            }
+        }
+    }
+    batches.push(batch);
+    return batches;
+};
+
+module.exports.predicateBatchAsync = async function <T, A>(batcher: PredicateBatcherAsync<T, A>): Promise<T[][]> {
+    const batches: T[][] = [];
+    let batch: T[] = [];
+    const { executor, initial, persistAccumulator } = batcher;
+    let accumulator: A = initial;
+    for (let element of this) {
+        const { updated, makeNextBatch } = await executor(element, accumulator);
+        accumulator = updated;
+        if (!makeNextBatch) {
+            batch.push(element);
+        } else {
+            batches.push(batch);
+            batch = [element];
+            if (!persistAccumulator) {
+                accumulator = initial;
+            }
+        }
+    }
+    batches.push(batch);
+    return batches;
+};
+
+module.exports.batch = function <T, A>(batcher: Batcher<T, A>): T[][] {
+    if ("executor" in batcher) {
+        return this.predicateBatch(batcher);
+    } else {
+        return this.fixedBatch(batcher);
+    }
+};
+
+module.exports.batchAsync = async function <T, A>(batcher: BatcherAsync<T, A>): Promise<T[][]> {
+    if ("executor" in batcher) {
+        return this.predicateBatchAsync(batcher);
+    } else {
+        return this.fixedBatch(batcher);
+    }
+};
+
+module.exports.batchedForEach = function <I, A>(batcher: Batcher<I, A>, handler: BatchHandlerSync<I>): void {
+    if (this.length) {
+        let completed = 0;
+        const batches = this.batch(batcher);
+        const quota = batches.length;
+        for (let batch of batches) {
+            const context: BatchContext = {
+                completedBatches: completed,
+                remainingBatches: quota - completed,
+            };
+            handler(batch, context);
+            completed++;
+        }
+    }
+};
+
+module.exports.batchedMap = function <I, O, A>(batcher: Batcher<I, A>, handler: BatchConverterSync<I, O>): O[] {
+    if (!this.length) {
+        return [];
+    }
+    let collector: O[] = [];
+    let completed = 0;
+    const batches = this.batch(batcher);
+    const quota = batches.length;
+    for (let batch of batches) {
+        const context: BatchContext = {
+            completedBatches: completed,
+            remainingBatches: quota - completed,
+        };
+        collector.push(...handler(batch, context));
+        completed++;
+    }
+    return collector;
+};
+
+module.exports.batchedForEachAsync = async function <I, A>(batcher: BatcherAsync<I, A>, handler: BatchHandler<I>): Promise<void> {
+    if (this.length) {
+        let completed = 0;
+        const batches = await this.batchAsync(batcher);
+        const quota = batches.length;
+        for (let batch of batches) {
+            const context: BatchContext = {
+                completedBatches: completed,
+                remainingBatches: quota - completed,
+            };
+            await handler(batch, context);
+            completed++;
+        }
+    }
+};
+
+module.exports.batchedMapAsync = async function <I, O, A>(batcher: BatcherAsync<I, A>, handler: BatchConverter<I, O>): Promise<O[]> {
+    if (!this.length) {
+        return [];
+    }
+    let collector: O[] = [];
+    let completed = 0;
+    const batches = await this.batchAsync(batcher);
+    const quota = batches.length;
+    for (let batch of batches) {
+        const context: BatchContext = {
+            completedBatches: completed,
+            remainingBatches: quota - completed,
+        };
+        collector.push(...(await handler(batch, context)));
+        completed++;
+    }
+    return collector;
+};
+
+module.exports.batchedForEachInterval = async function <I, A>(batcher: BatcherAsync<I, A>, handler: BatchHandler<I>, interval: Interval): Promise<void> {
+    if (!this.length) {
+        return;
+    }
+    const batches = await this.batchAsync(batcher);
+    const quota = batches.length;
+    return new Promise<void>(async resolve => {
+        const iterator = batches[Symbol.iterator]();
+        let completed = 0;
+        while (true) {
+            const next = iterator.next();
+            await new Promise<void>(resolve => {
+                setTimeout(async () => {
+                    const batch = next.value;
+                    const context: BatchContext = {
+                        completedBatches: completed,
+                        remainingBatches: quota - completed,
+                    };
+                    await handler(batch, context);
+                    resolve();
+                }, convert(interval));
+            });
+            if (++completed === quota) {
+                break;
+            }
+        }
+        resolve();
+    });
+};
+
+module.exports.batchedMapInterval = async function <I, O, A>(batcher: BatcherAsync<I, A>, handler: BatchConverter<I, O>, interval: Interval): Promise<O[]> {
+    if (!this.length) {
+        return [];
+    }
+    let collector: O[] = [];
+    const batches = await this.batchAsync(batcher);
+    const quota = batches.length;
+    return new Promise<O[]>(async resolve => {
+        const iterator = batches[Symbol.iterator]();
+        let completed = 0;
+        while (true) {
+            const next = iterator.next();
+            await new Promise<void>(resolve => {
+                setTimeout(async () => {
+                    const batch = next.value;
+                    const context: BatchContext = {
+                        completedBatches: completed,
+                        remainingBatches: quota - completed,
+                    };
+                    collector.push(...(await handler(batch, context)));
+                    resolve();
+                }, convert(interval));
+            });
+            if (++completed === quota) {
+                resolve(collector);
+                break;
+            }
+        }
+    });
+};
+
+module.exports.lastElement = function <T>() {
+    if (!this.length) {
+        return undefined;
+    }
+    const last: T = this[this.length - 1];
+    return last;
+};
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