blob: 4152b16a463c5ef772d54ec2aa6617d22e72f897 [file] [log] [blame]
// @flow strict
declare function flatMap<T, U>(
list: $ReadOnlyArray<T>,
fn: (item: T, index: number) => $ReadOnlyArray<U> | U,
): Array<U>;
const flatMapMethod = Array.prototype.flatMap;
/* eslint-disable no-redeclare */
// $FlowFixMe
const flatMap = flatMapMethod
? function(list, fn) {
return flatMapMethod.call(list, fn);
}
: function(list, fn) {
let result = [];
for (const item of list) {
const value = fn(item);
if (Array.isArray(value)) {
result = result.concat(value);
} else {
result.push(value);
}
}
return result;
};
export default flatMap;