Core Push Functions

Core functions to create and run Push Lines.

composeOperations

composeOperations(operations) => PushOperation

Composes several existing operations into a new one.

import { composeOperations, pushArray, flattenArrays, zip } from "@undercut/push";
function interleave(...sources) {    const operations = [        zip(...sources),        flattenArrays()    ];
    return composeOperations(operations);}
const source = [1, 3, 5];const pipeline = [    interleave([2, 4, 6])];
const result = pushArray(pipeline, source);
console.log(result); // [1, 2, 3, 4, 5, 6]

push

push(target, pipeline, source) => target

Executes the pipeline by pushing items from an iterable source to the target and returns the target back.

import { push, filter, map, skip, toArray } from "@undercut/push";
const source = [1, 2, 3, 4, 5, 6, 7];const pipeline = [    skip(2),    filter(x => x % 3),    map(x => x * 2)];const target = toArray();
const target2 = push(target, pipeline, source); // target2 === target
// `toArray` target has `values` property.console.log(target.values); // [8, 10, 14]

pushArray

pushArray(pipeline, source) => Array

Same as push, but target is implicitly set to toArray() and its values property is returned.

import { pushArray, filter, map, skip } from "@undercut/push";
const source = [1, 2, 3, 4, 5, 6, 7];const pipeline = [    skip(2),    filter(x => x % 3),    map(x => x * 2)];
const result = pushArray(pipeline, source);
console.log(result); // [8, 10, 14]

pushLine

pushLine(pipeline, target) => Observer

Creates a Push Line.

Usually, you will push an item in an event handler like button click, etc.

import { pushLine, append, compact, skip, toArray } from "@undercut/push";
const target = toArray();const pipeline = [    append(4, 5),    compact(),    skip(2)];
const numbersObserver = pushLine(pipeline, target); // No evaluation happens at this step.
[0, 1, 2, 3].forEach(x => numbersObserver.next(x)); // Push items.
numbersObserver.return(); // Close the observer.
console.log(target.values); // [3, 4, 5]

pushValue

pushValue(pipeline, source) => item

Same as push, but target is implicitly set to toValue(), which result value it returns.

import { pushValue, filter, map, skip } from "@undercut/push";
const source = [1, 2, 3, 4, 5, 6, 7];const pipeline = [    skip(2),    filter(x => x % 3),    map(x => x * 2)];
const result = pushValue(pipeline, source);
console.log(result); // 8