javascript - Should you ever use local inner functions? -
which of these seen better when writing javascript. foo, bar, , baz specific function won't used anywhere else in other functions.
function() { foo(); bar(); baz(); } function foo() { //lines of code } function bar() { //lines of code } function baz() { //lines of code } or
function() { function foo() { //lines of code } foo(); function bar() { //lines of code } bar(); function baz() { //lines of code } baz(); } the advantages of first is more efficient since if calling function more once other functions need created once. easier read main outer function 3 lines long , not longer.
the advantage can think second keeps these functions private outer function , not accessible rest of file since these functions not used anywhere else. making things public when shouldn't need bad less important in javascript situations this.
is possible choose differently depending on how function called or else?
if want functions publicly available themselves, declare them separately
function foo() {} // public, created once function bar() {} // public, created once function baz() {} // public, created once var foobarbaz = function() { // public, created once foo(); bar(); baz(); };if want auxiliary functions able access scope of main function, trade-of have recreated each time call main function, place auxiliary function inside main one
var foobarbaz = function() { // public, created once function foo() {} // private, created @ each foobarbaz call function bar() {} // private, created @ each foobarbaz call function baz() {} // private, created @ each foobarbaz call foo(); bar(); baz(); };if want keep auxiliary functions private, , don't want recreate them each time call main function, use iife
var foobarbaz = (function() { // iife function foo() {} // private, created once function bar() {} // private, created once function baz() {} // private, created once return function() { // public, created once foo(); bar(); baz(); }; })();
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