operator head.ts

100% Statements 6/6

100% Branches 2/2

100% Functions 1/1

100% Lines 5/5

Press n or j to go to the next uncovered block, b, p or k for the previous block.


1
2
3
4
5
6
7
8
9
10  
 
1x
4x
4x
2x
 
2x
 
  import {Seq} from 'fnxt/fnxt-types';
 
export const head = <E>(seq: Seq<E>): E => {
  const next = seq[Symbol.iterator]().next();
  if (next.done) {
    throw Error('sequence is empty');
  }
  return next.value as E;
};