flatMap doesn't work in yarn test javascript

Question

I have some code in a component method of mine using flatMap. The code works just fine in the browser, but the flatMap method isn't there when running the code using yarn test. Has anyone ever seen something like this before?

● Click Events › should copy table data

TypeError: children.map(...).flatMap is not a function

  181 |     const dataKeys = children
  182 |       .map(({ $: { data: dataKey } }) => dataKey)
> 183 |       .flatMap(k => k.split(LEVEL_DELIMITER));
      |        ^

EDIT - reproducible example: created a CRA base and added this simple test:

it('can flatMap', () => {
    [1, 2, 3, 4].flatMap(x => [x * 2]);
});

got the same error:

 FAIL  src/App.test.js
● can flatMap

TypeError: [1,2,3,4].flatMap is not a function

  at Object.<anonymous>.it (src/App.test.js:12:16)
      at new Promise (<anonymous>)
  at Promise.resolve.then.el (node_modules/p-map/index.js:46:16)
      at <anonymous>
  at process._tickCallback (internal/process/next_tick.js:188:7)

✓ renders without crashing (4ms)
✕ can flatMap

Answer 1

A coworker of mine found the solution. Apparently flatMap isn't supported by Node.js:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flatMap#Browser_compatibility

---

flatMap is now supported in node 11+ as said below, see the same link.