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get: value by path

Write a function get(obj, path, defaultValue), like lodash's. The path is a string like "a.b[0].c" or an array of keys ["a", "b", 0, "c"].

If you hit null or undefined along the way, or the final value is undefined, return defaultValue. Values 0 and null at the end of the path are real and returned as is.

function get(obj, path, defaultValue) {
  // ...
}

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Tests (7)

const obj = { a: { b: [{ c: 42 }] } };
expect(get(obj, 'a.b[0].c')).toBe(42);

expect(get({ a: { b: 1 } }, ['a', 'b'])).toBe(1);

expect(get({ list: [10, 20] }, 'list[1]')).toBe(20);

expect(get({ a: null }, 'a.b.c', 'none')).toBe('none');

○
```
expect(get({}, 'x.y')).toBe(undefined);
```

expect(get({ a: { b: 0 } }, 'a.b', 5)).toBe(0);

expect(get({ a: { b: null } }, 'a.b', 5)).toBe(null);