Prefer var declarations be placed at the top of their scope JS-0102
Anti-pattern
Minor
3 months ago
—
3 months old
All 'var' declarations must be at the top of the function scope
174 window.location.hash = e.target.hash.replace("#", "#" + prefix);
175 })
176 // Read any hash links
177 var hash = document.location.hash;178 if (hash) {
179 $('.nav-tabs a[href="'+hash.replace(prefix,"")+'"]').tab('show');
180 }All 'var' declarations must be at the top of the function scope
169 });
170 // https://stackoverflow.com/questions/7862233
171 // Change hash for page-reload
172 var prefix = "tab_";173 $('.nav-tabs.maintabs a').on('shown.bs.tab', function (e) {
174 window.location.hash = e.target.hash.replace("#", "#" + prefix);
175 })All 'var' declarations must be at the top of the function scope
142
143 var currentdiv = TABS[CURRENTTAB] +"-ui";
144 $("#"+currentdiv).css("display", "block");
145 var btndiv = TABS[CURRENTTAB] +"-btn";146 $("#"+btndiv).removeClass().addClass("btn btn-primary");
147
148 $('#next-btn').prop('disabled', ((CURRENTTAB + 1) == TABS.length));All 'var' declarations must be at the top of the function scope
140 $("#"+btndiv).removeClass().addClass("btn btn-default");
141 CURRENTTAB = TABS.indexOf(tabtitle);
142
143 var currentdiv = TABS[CURRENTTAB] +"-ui";144 $("#"+currentdiv).css("display", "block");
145 var btndiv = TABS[CURRENTTAB] +"-btn";
146 $("#"+btndiv).removeClass().addClass("btn btn-primary");All 'var' declarations must be at the top of the function scope
136 var tabtitle = $(this).attr("id").replace("-btn", "");
137 var currentdiv = TABS[CURRENTTAB] +"-ui";
138 $("#"+currentdiv).css("display", "none");
139 var btndiv = TABS[CURRENTTAB] +"-btn";140 $("#"+btndiv).removeClass().addClass("btn btn-default");
141 CURRENTTAB = TABS.indexOf(tabtitle);
142
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++) {}
}