Add subtract to math.js · Pull request #5 · flagon-io/automation-lab

1	−	# Checks Docker on g1t's hosted runners: a service container reached by
2	−	# name, a step run in an image, a build, and a job inside a container.
3	−	name: Docker
4	−
5	−	on:
6	−	workflow_dispatch:
7	−
8	−	permissions:
9	−	contents: read
10	−
11	−	jobs:
12	−	services:
13	−	name: Services and docker run
14	−	runs-on: ubuntu-latest
15	−	timeout-minutes: 15
16	−	services:
17	−	redis:
18	−	image: redis:7-alpine
19	−	options: >-
20	−	--health-cmd "redis-cli ping"
21	−	--health-interval 2s
22	−	--health-timeout 2s
23	−	--health-retries 15
24	−	ports:
25	−	- 6379:6379
26	−	steps:
27	−	- uses: actions/checkout@v5
28	−	- name: Docker is there
29	−	run: docker version
30	−	- name: Reach the service by name
31	−	run: docker run --rm redis:7-alpine redis-cli -h redis ping
32	−	- name: Build an image
33	−	run: \|
34	−	printf 'FROM alpine:3.20\nRUN echo built > /built\nCMD cat /built\n' > Dockerfile.smoke
35	−	docker build -t smoke:latest -f Dockerfile.smoke .
36	−	docker run --rm smoke:latest
37	−	- name: A step in an image
38	−	uses: docker://alpine:3.20
39	−	with:
40	−	args: echo hello from a docker step
41	−
42	−	container:
43	−	name: Job in a container
44	−	runs-on: ubuntu-latest
45	−	timeout-minutes: 15
46	−	container:
47	−	image: node:24-bookworm-slim
48	−	steps:
49	−	- uses: actions/checkout@v5
50	−	- run: node --version && cat /etc/os-release \| head -2

1	1		# automation lab
2		−
3		−	## Functions
4		−
5		−	All functions are exported from `math.js`.
6		−
7		−	```js
8		−	const { add, multiply, power, mean, median, standard_deviation } = require("./math");
9		−	```
10		−
11		−	- `add(a, b)`: returns the sum of `a` and `b`.
12		−	```js
13		−	add(2, 3); // 5
14		−	```
15		−	- `multiply(a, b)`: returns the product of `a` and `b`.
16		−	```js
17		−	multiply(4, 5); // 20
18		−	```
19		−	- `power(base, exponent)`: returns `base` raised to a whole-number `exponent`; throws a `RangeError` if `exponent` is negative.
20		−	```js
21		−	power(2, 3); // 8
22		−	```
23		−	- `mean(numbers)`: returns the average of an array of numbers; throws a `TypeError` if the array is empty.
24		−	```js
25		−	mean([1, 2, 3, 4]); // 2.5
26		−	```
27		−	- `median(numbers)`: returns the middle value (the average of the two middle values when the length is even); throws a `TypeError` if the array is empty.
28		−	```js
29		−	median([3, 1, 2]); // 2
30		−	median([1, 2, 3, 4]); // 2.5
31		−	```
32		−	- `standard_deviation(numbers)`: returns the population standard deviation; throws a `TypeError` if the array is empty.
33		−	```js
34		−	standard_deviation([2, 4, 4, 4, 5, 5, 7, 9]); // 2
35		−	```

9	9		return a * b;
10	10		}
11	11
	12	+	/** Returns a minus b. */
	13	+	function subtract(a, b) {
	14	+	return a - b;
	15	+	}
	16	+
12	17		/** Returns base raised to the whole-number exponent; throws a RangeError if exponent is negative. */
13	18		function power(base, exponent) {
14	19		if (exponent < 0) {
⋯
46	51		return Math.sqrt(variance);
47	52		}
48	53
49		−	module.exports = { add, multiply, power, mean, median, standard_deviation };
	54	+	module.exports = { add, multiply, subtract, power, mean, median, standard_deviation };

1	1		const assert = require("node:assert");
2	2		const math = require("./math");
	3	+	assert.strictEqual(math.subtract(5, 3), 2);
3	4
4	5		assert.strictEqual(math.add(2, 3), 5);
5	6		assert.strictEqual(math.multiply(4, 5), 20);
6	7		assert.strictEqual(math.power(2, 10), 1024);
7	8		assert.strictEqual(math.power(5, 0), 1);
8	9		assert.throws(() => math.power(2, -1), RangeError);
9		−	assert.strictEqual(math.mean([1, 2, 3]), 2);
10	10		assert.strictEqual(math.mean([1, 2, 3, 4]), 2.5);
11		−	assert.strictEqual(math.median([1, 2, 3]), 2);
12	11		assert.strictEqual(math.median([3, 1, 2]), 2);
13	12		assert.strictEqual(math.median([4, 1, 3, 2]), 2.5);
14		−	assert.strictEqual(math.standard_deviation([1, 2, 3]), Math.sqrt(2 / 3));
15	13		assert.strictEqual(math.standard_deviation([2, 4, 4, 4, 5, 5, 7, 9]), 2);
16	14		for (const fn of [math.mean, math.median, math.standard_deviation]) {
17	15		assert.throws(() => fn([]), TypeError);