Add toPairs snippet

snippets/toPairs.md

@@ -0,0 +1,23 @@
+---
+title: toPairs
+tags: object,array,intermediate
+---
+
+Creates an array of key-value pair arrays from an object or other iterable (object, array, string, set etc.).
+
+Check if `Symbol.iterator` is defined and, if so, use `Array.prototype.entries()` to get an iterator for the given iterable, `Array.from()` to convert the result to an array of key-value pair arrays.
+If `Symbol.iterator` is not defined for `obj`, use `Object.entries()` instead.
+
+```js
+const toPairs = obj =>
+  obj[Symbol.iterator] instanceof Function && obj.entries instanceof Function
+    ? Array.from(obj.entries())
+    : Object.entries(obj);
+```
+
+```js
+toPairs({ a: 1, b: 2 }); // [ ['a', 1], ['b', 2] ]
+toPairs([2, 4, 8]); // [ [0, 2], [1, 4], [2, 8] ]
+toPairs('shy'); // [ ['0', 's'], ['1', 'h'], ['2', 'y'] ]
+toPairs(new Set(['a', 'b', 'c', 'a'])); // [ ['a', 'a'], ['b', 'b'], ['c', 'c'] ]
+```

test/toPairs.test.js

@@ -0,0 +1,17 @@
+const {toPairs} = require('./_30s.js');
+
+test('toPairs is a Function', () => {
+  expect(toPairs).toBeInstanceOf(Function);
+});
+test('Creates an array of key-value pair arrays from an object.', () => {
+  expect(toPairs({ a: 1, b: 2 })).toEqual([['a', 1], ['b', 2]]);
+});
+test('Creates an array of key-value pair arrays from an array.', () => {
+  expect(toPairs([2, 4, 8])).toEqual([[0, 2], [1, 4], [2, 8]]);
+});
+test('Creates an array of key-value pair arrays from a string.', () => {
+  expect(toPairs('shy')).toEqual([['0', 's'], ['1', 'h'], ['2', 'y']]);
+});
+test('Creates an array of key-value pair arrays from a set.', () => {
+  expect(toPairs(new Set(['a', 'b', 'c', 'a']))).toEqual([['a', 'a'], ['b', 'b'], ['c', 'c']]);
+});