Linear Search

# Linear Search

Zerethon Official Sample `linear-search`, version 1.1.0, Node.js 22.

- `linear_search.js` — the algorithm, as shown in Zerethon Tools
- `main.js` — entry file: a short demonstration
- `test_linear_search.js` — checks; set it as the entry file to run them

This project is your own copy. Changing it never changes the official sample.
See the algorithm animated: https://tools.zerethon.com/linear-search-visualizer

// Linear Search (Zerethon Official Sample: linear-search 1.1.0).

// Returns the index of target, or -1. Works on any (unsorted) array.
function linearSearch(a, target) {
    for (let i = 0; i < a.length; i++) {
        if (a[i] === target) return i;
    }
    return -1;
}

module.exports = { linearSearch };

const { linearSearch } = require('./linear_search');

const numbers = [38, 27, 43, 3, 9, 82, 10, 27];
console.log(`List: [${numbers.join(', ')}]`);
for (const target of [43, 27, 38, 5]) {
    const index = linearSearch(numbers, target);
    const result = index !== -1 ? `found at index ${index}` : 'not found';
    console.log(`search ${String(target).padStart(2)}: ${result}`);
}

// Checks for linearSearch. To run them, set this file as the entry file
// (the ▶ button next to it in Files) and press Run.
const assert = require('assert');
const { linearSearch } = require('./linear_search');

const cases = [
    [[], 1, -1],
    [[4], 4, 0],
    [[4], 5, -1],
    [[9, 3, 7], 9, 0],
    [[9, 3, 7], 7, 2],
    [[5, 1, 5, 1], 1, 1], // the first match wins
    [Array.from({ length: 100 }, (_, i) => 100 - i), 1, 99],
];

for (const [a, target, expected] of cases) {
    assert.strictEqual(linearSearch(a, target), expected, `linearSearch([${a.slice(0, 5)}...], ${target})`);
}

console.log(`All ${cases.length} checks passed.`);