Question

I might be asking the wrong question here, so I apologize if the answer is on another thread… but I’ve looked around to no avail.

in a snippet, why doesn’t this work?

array = [72,69,76,76,79];
document.write(String.fromCharCode(array));

I’m collecting key events in an array and want to be able to write them out as chars when prompted. And though this works:

document.write(String.fromCharCode(72,69,76,76,79));

I can’t seem to get it to work when I pass it along as an array. I’ve also tried to convert the array toString() first, as well array.join(“,”); to create a comma separated list …yet nothing. Any ideas? Is there a better way to convert the values I collect in my array into chars?

Answer 1

You could use the function’s apply() method…

document.write(String.fromCharCode.apply(null, array));

jsFiddle.

ES6 can use the spread operator…

document.write(String.fromCharCode(...array));

You could also use the array’s reduce() method, but older IEs do not support it. You could shim it, but the apply() method is better supported.

document.write(array.reduce(function(str, charIndex) {
    return str += String.fromCharCode(charIndex);
}, ''));​

jsFiddle.