Default parameters should be defined at the last JS-0106
Anti-pattern
Minor
a year ago
—
a year old
Default parameters should be last.
60 'en_US': require('../languages/en_US.json')
61}
62
63function translate(lang="tr_TR", value) {64
65 if (!languages.includes(lang)) lang = 'tr_TR';
66Default parameters should be last.
67 'en_US': require('../languages/en_US.json')
68}
69
70function translate(lang = "tr_TR", value) {71
72 if (!languages.includes(lang)) lang = 'tr_TR';
73
Description
Putting default parameter at last allows function calls to omit optional tail arguments.
// Correct: optional argument can be omitted
function createUser(id, isAdmin = false) {}
createUser("tabby")
// Incorrect: optional argument can **not** be omitted
function createUser(isAdmin = false, id) {}
createUser(undefined, "tabby")
Bad Practice
function f(a = 0, b) {}
function f(a, b = 0, c) {}
Recommended
function f(a, b = 0) {}