Reduce array to a single string

Question

I would like to use the reduce function instead of doing this:

var result = ''; authors.forEach(     function(author) {         result += author.name + ', ';     } ); console.log(result); 

So in the array authors there are several names. Now I want to build a string with this names, separated by comma (except the last one).

var result = authors.reduce(function (author, index) {     return author + ' '; }, ''); console.log(result); 

Answer 1

A flurry of answers just came in and here is one more!

The first option is using the native js join method which eliminates the need for reduce. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join

var authors = ['some author', 'another author', 'last author']; var authorString = authors.join(","); console.log(authorString); 

IMPORTANT - if you're array contains objects, then you might want to map it before joining:

var authors = [{name: 'some author'},{name: 'another author'},{name: 'last author'}] var authorString = authors.map(function(author){     return author.name; }).join(","); console.log(authorString); 

or, if you're really fired up about using reduce, just make sure you use the previous value, current value and index when passing in the callback. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

var authorString = authors.reduce(function(prevVal,currVal,idx){     return idx == 0 ? currVal : prevVal + ', ' + currVal; }, '') console.log(authorString); 

IMPORTANT - again if your array contains objects then you will want to make sure you are using the 'name property':

var authors = [{name: 'some author'},{name: 'another author'},{name: 'last author'}]; var authorString = authors.reduce(function(prevVal,currVal,idx){     return idx == 0 ? currVal.name : prevVal + ', ' + currVal.name; }, '') console.log(authorString);