unshift

import { unshift } from '@accelint/core';

// Add element to start
const withZero = unshift([1, 2, 3, 4])(0);
// [0, 1, 2, 3, 4]

// Partial application
const addToNumbers = unshift([2, 3, 4]);
addToNumbers(1); // [1, 2, 3, 4]

function unshift<T>(
  arr: T[]
): (x: T) => T[]

import { unshift } from '@accelint/core';

let numbers: number[] = [];
numbers = unshift(numbers)(3);
numbers = unshift(numbers)(2);
numbers = unshift(numbers)(1);
// [1, 2, 3]

// Original array unchanged
const original = [2, 3, 4];
const extended = unshift(original)(1);
// original: [2, 3, 4]
// extended: [1, 2, 3, 4]

import { unshift, shift } from '@accelint/core';

// Push to stack
let stack: number[] = [2, 3, 4];
stack = unshift(stack)(1);
// [1, 2, 3, 4]

// Pop from stack
const [top, newStack] = shift(stack);
// top: 1
// newStack: [2, 3, 4]

import { unshift } from '@accelint/core';

interface LogEntry {
  timestamp: Date;
  message: string;
}

const logs: LogEntry[] = [
  { timestamp: new Date('2026-07-13T10:00:00'), message: 'Event 1' },
  { timestamp: new Date('2026-07-13T10:01:00'), message: 'Event 2' }
];

const newLog = { timestamp: new Date('2026-07-13T09:59:00'), message: 'Event 0' };
const updatedLogs = unshift(logs)(newLog);
// newLog is now at the start

import { unshift, map, pipe } from '@accelint/core';

const addHeaderAndDouble = (header: number) =>
  pipe(
    map((x: number) => x * 2),
    unshift(header)
  );

addHeaderAndDouble(0)([1, 2, 3]);
// [0, 2, 4, 6]