Build: a utility package with its own tests

// Turns a title into a URL slug: "Tea & Cake!" -> "tea-cake".
export function slugify(text) {
  return text.toLowerCase();
}

console.log(slugify("Tea & Cake!"));

import {test} from 'node:test';
import assert from 'node:assert/strict';
import {slugify} from './main.js';

test('Tea & Cake! becomes tea-cake', () => {
  assert.equal(slugify('Tea & Cake!'), 'tea-cake', `slugify('Tea & Cake!') returned ${JSON.stringify(slugify('Tea & Cake!'))}`);
});

test('runs of spaces and signs become one hyphen, none at the ends', () => {
  const got = slugify('  Hello,   World  ');
  assert.equal(got, 'hello-world', `slugify('  Hello,   World  ') returned ${JSON.stringify(got)}`);
});

test('digits stay', () => {
  assert.equal(slugify('Top 10 Tips'), 'top-10-tips', `slugify('Top 10 Tips') returned ${JSON.stringify(slugify('Top 10 Tips'))}`);
});

test('accents are removed: Crème Brûlée becomes creme-brulee', () => {
  const got = slugify('Crème Brûlée');
  assert.equal(got, 'creme-brulee', `slugify('Crème Brûlée') returned ${JSON.stringify(got)}`);
});

test('a value that is not a string throws a TypeError', () => {
  assert.throws(() => slugify(42), TypeError, 'slugify(42) should throw a TypeError');
});

{
  "type": "module"
}

// Shortens text to at most max characters, ending with an ellipsis: "A long…".
export const ELLIPSIS = "…";

export function truncate(text, max) {
  return text;
}

console.log(truncate("A long title", 7));

import {test} from 'node:test';
import assert from 'node:assert/strict';
import {truncate} from './main.js';

test('text that fits comes back unchanged', () => {
  assert.equal(truncate('Tea', 5), 'Tea', `truncate('Tea', 5) returned ${JSON.stringify(truncate('Tea', 5))}`);
  assert.equal(truncate('Hello', 5), 'Hello', `truncate('Hello', 5) returned ${JSON.stringify(truncate('Hello', 5))}`);
});

test('long text ends with …: truncate("A long title", 7) is "A long…"', () => {
  const got = truncate('A long title', 7);
  assert.equal(got, 'A long…', `truncate('A long title', 7) returned ${JSON.stringify(got)}`);
});

test('no space before the …: truncate("Hello world", 7) is "Hello…"', () => {
  const got = truncate('Hello world', 7);
  assert.equal(got, 'Hello…', `truncate('Hello world', 7) returned ${JSON.stringify(got)}`);
});

test('the result is never longer than max', () => {
  for (let max = 1; max <= 12; max++) {
    const got = truncate('A long title here', max);
    assert.ok(got.length <= max, `truncate('A long title here', ${max}) returned ${JSON.stringify(got)}, ${got.length} characters`);
  }
});

test('a max that is not a whole number from 1 throws a RangeError', () => {
  assert.throws(() => truncate('Tea', 0), RangeError, 'truncate("Tea", 0) should throw a RangeError');
  assert.throws(() => truncate('Tea', 2.5), RangeError, 'truncate("Tea", 2.5) should throw a RangeError');
});

test('text that is not a string throws a TypeError', () => {
  assert.throws(() => truncate(null, 5), TypeError, 'truncate(null, 5) should throw a TypeError');
});

{
  "type": "module"
}

// The entry file of textkit: what it exports is the package.
export * from "./slug.js";
export * from "./truncate.js";

import {test} from 'node:test';
import assert from 'node:assert/strict';
import * as textkit from './main.js';

test('exports slugify and truncate, and nothing else', () => {
  const names = Object.keys(textkit).sort();
  assert.deepEqual(names, ['slugify', 'truncate'], `the entry exports ${JSON.stringify(names)}`);
});

test('the functions work through the entry file', () => {
  assert.equal(textkit.slugify('Tea & Cake!'), 'tea-cake', 'slugify through the entry should give tea-cake');
  assert.equal(textkit.truncate('A long title', 7), 'A long…', 'truncate through the entry should give A long…');
});

test('has no default export', () => {
  assert.equal('default' in textkit, false, 'the entry should have named exports only');
});

// Turns a title into a URL slug: "Tea & Cake!" -> "tea-cake".
export function slugify(text) {
  if (typeof text !== "string") throw new TypeError("slugify expects a string, got " + typeof text);
  return text
    .normalize("NFD")
    .replace(/[\u0300-\u036f]/g, "")
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "");
}

// Shortens text to at most max characters, ending with an ellipsis: "A long…".
export const ELLIPSIS = "…";

export function truncate(text, max) {
  if (typeof text !== "string") throw new TypeError("truncate expects a string, got " + typeof text);
  if (!Number.isInteger(max) || max < 1) throw new RangeError("max must be a whole number from 1, got " + max);
  if (text.length <= max) return text;
  return text.slice(0, max - 1).trimEnd() + ELLIPSIS;
}

{
  "type": "module"
}