Found reassigning const variables JS-0230
Bug risk
Major
4 months ago
—
a year old
'img_res' is constant
115 throw new Error('invalid url')
116 }
117
118 img_res = await request_remote_image(url)119 status_code = Math.floor(img_res.statusCode / 100)
120 }
121
Description
Re-assigning a variable that was declared with the const keyword can lead to a TypeError.
const pi = 3.14159
pi = 3.14 // Uncaught TypeError: Assignment to constant variable.
Bad Practice
const a = 0;
a = 1;
const b = 0;
b += 1;
const c = 0;
++c;
Recommended
const a = 0;
console.log(a);
for (const k in [1, 2, 3]) { // `a` is re-defined (not modified) on each loop step.
console.log(k);
}
for (const x of [1, 2, 3]) { // `a` is re-defined (not modified) on each loop step.
console.log(x);
}