Add accumulate

snippets/accumulate.md

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+---
+title: accumulate
+tags: math,array,beginner
+---
+
+Returns an array of partial sums.
+
+Use `Array.prototype.reduce()`, `Array.prototype.slice(-1)` and the unary `+` operator to add each value to the unary array containing the previous sum.
+
+```js
+const accumulate = (...nums) => nums.reduce((acc, n) => [...acc, n + +acc.slice(-1)],[]);
+```
+
+```js
+accumulate(1, 2, 3, 4); // [1, 3, 6, 10]
+accumulate(...[1, 2, 3, 4]); // [1, 3, 6, 10]
+```