Prefer var declarations be placed at the top of their scope JS-0102
Anti-pattern
Minor
3 months ago
—
a year old
All 'var' declarations must be at the top of the function scope
868 }
869
870 if (this.colorMode !== ColorMode.Feed) {
871 var extruder = Number(tokenString.substring(1)) % this.extruderCount; 872 if (extruder < 0) extruder = 0;
873 this.currentColor = this.tools[extruder]?.color?.clone() ?? new Color3(1, 0, 0);
874 }All 'var' declarations must be at the top of the function scope
929
930 chunk(arr, chunkSize) {
931 var R = [];
932 for (var i = 0, len = arr.length; i < len; i += chunkSize) R.push(arr.slice(i, i + chunkSize)); 933 return R;
934 }
935All 'var' declarations must be at the top of the function scope
626 return;
627 }
628
629 var lines = file.split('\n'); 630
631 //Extract metadata from slicer to set render settings
632 this.slicer.processComments(lines, this);All 'var' declarations must be at the top of the function scope
24 var dynamicTexture = new DynamicTexture('DynamicTexture', 50, this.scene, true);
25 dynamicTexture.hasAlpha = true;
26 dynamicTexture.drawText(text, 5, 40, 'bold 36px Arial', color, 'transparent', true);
27 var plane = Mesh.CreatePlane('TextPlane', size, this.scene, true); 28 plane.material = new StandardMaterial('TextPlaneMaterial', this.scene);
29 plane.material.backFaceCulling = false;
30 plane.material.specularColor = new Color3(0, 0, 0); All 'var' declarations must be at the top of the function scope
89 box.material= edgeMaterial;
90}
91
92var ViewBoxCallback; 93
94export function registerViewBoxCallback(func) {
95 ViewBoxCallback = func;
Description
Declare variables at the top of their scope as it improves code readability, performance and also helps in code navigation.
The vars-on-top rule generates warnings when variable declarations are not used serially at the top of a function scope or the top of a program. By default variable declarations are always moved (“hoisted”) invisibly to the top of their containing scope by the JavaScript interpreter. This rule forces the programmer to represent that behavior by manually moving the variable declaration to the top of its containing scope.
Bad Practice
// Variable declarations in a block:
function doSomething() {
var first;
if (true) {
first = true;
}
var second;
}
// Variable declaration in for initializer:
function doSomething() {
for (var i=0; i<10; i++) {}
}
Recommended
function doSomething() {
var first;
var second; //multiple declarations are allowed at the top
if (true) {
first = true;
}
}
function doSomething() {
var i;
for (i=0; i<10; i++) {}
}