2 ms·
From https://stackoverflow.com/questions/22036300/what-is-1-2-3-mapparseint-result https://stackoverflow.com/questions/22036300/what-is-1-2-3-m... // Consider:
by hoblaypop 5y ago
From https://stackoverflow.com/questions/22036300/what-is-1-2-3-mapparseint-result https://stackoverflow.com/questions/22036300/what-is-1-2-3-m...
// Consider:
["1", "2", "3"].map(parseInt);
// While one could expect [1, 2, 3]
// The actual result is [1, NaN, NaN]
// parseInt is often used with one argument, but takes two. The second being the radix
// To the callback function, Array.prototype.map passes 3 arguments:
// the element, the index, the array
// The third argument is ignored by parseInt, but not the second one,
// hence the possible confusion. See the blog post for more details
function returnInt(element){
return parseInt(element,10);
}
["1", "2", "3"].map(returnInt);
// Actual result is an array of numbers (as expected)