We have an array of arrays like this −
const arr = [ ['foo', 'bar', 'hey', 'oi'], ['foo', 'bar', 'hey'], ['foo', 'bar', 'anything'], ['bar', 'anything'] ]
We are required to write a JavaScript function that takes in such array and returns an array that contains all the strings which appears in all the subarrays.
Let's write the code for this function
Example
const arr = [ ['foo', 'bar', 'hey', 'oi'], ['foo', 'bar', 'hey'], ['foo', 'bar', 'anything'], ['bar', 'anything'] ] const commonArray = arr => { return arr.reduce((acc, val, index) => { return acc.filter(el => val.indexOf(el) !== -1); }); }; console.log(commonArray(arr));
Output
The output in the console will be −
['bar']