Added Midpoint.js

snippets/midpoint.md

@@ -0,0 +1,24 @@
+### midpoint
+
+Calculates the midpoint between two pairs of x and y points.
+
+Takes in two pairs of (x,y) points, calculates the midpoint between the x's, the midpoint between the y's, and returns the coordinates in an array.
+
+```js
+const midpoint = (x1, y1, x2, y2) => {
+  let points = new Array(2);
+  let first_point = (x1 + x2) / 2;
+  let second_point = (y1 + y2) / 2;
+
+  points[0] = first_point;
+  points[1] = second_point;
+  return points;
+};
+```
+
+```js
+midpoint(2, 2, 4, 4); // [3, 3]
+midpoint(4, 4, 6, 6); // [5, 5]
+midpoint(1, 3, 2, 4); // [1.5, 3.5]
+```
+

tag_database

@@ -186,6 +186,7 @@ maxN:array,math,beginner
 median:math,array,intermediate
 memoize:function,advanced
 merge:object,array,intermediate
+midpoint:math,array,beginner
 minBy:math,array,function,beginner
 minDate:date,math,beginner
 minN:array,math,beginner

test/midpoint.test.js

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+const expect = require('expect');
+const {midpoint} = require('./_30s.js');
+
+test('midpoint is a Function', () => {
+  expect(midpoint).toBeInstanceOf(Function);
+});
+
+test('midpoint(2, 2, 4, 4) = [3, 3]', () => {
+  expect(midpoint(2, 2, 4, 4)).toEqual([3, 3])
+});
+
+test('midpoint(4, 4, 6, 6) = [5,5]', () => {
+  expect(midpoint(4, 4, 6, 6)).toEqual([5, 5])
+});
+
+test('midpoint(1, 3, 2, 4) = [3,3]', () => {
+  expect(midpoint(1, 3, 2, 4)).toEqual([1.5, 3.5])
+});
+
+test('midpoint(-2, 0, -2, 4) = [-2,2]', () => {
+  expect(midpoint(-2, 0, -2, 4)).toEqual([-2, 2])
+});
+
+test('midpoint(0, 0, 0, 0) = [0,0]', () => {
+  expect(midpoint(0, 0, 0, 0)).toEqual([0, 0])
+});
+
+test('midpoint(10, -10, 20, 30) = [15, 10]', () => {
+  expect(midpoint(10, -10, 20, 30)).toEqual([15, 10])
+});
+
+test('midpoint(7.5, -1.3, 2.7, 11.1) = [5.1, 4.8999999999999995]', () => {
+  expect(midpoint(7.5, -1.3, 2.7, 11.1)).toEqual([5.1, 4.8999999999999995])
+});
+