Uncaught SyntaxError: Unexpected token var in queue
I was implementing queue in JS, but the console keeps siplaying Uncaught SyntaxError: Unexpected token var. I used some online debugger and it points error in line 21. This is the code:
var queue = function (){
var elements = [];
var cur_element = 0;
var del_elem = 0;
return {
size: function() {
return cur_element-del_elem;
},
empty: function() {
return cur_element == 0;
},
front: function() {
if(!this.empty()){
return elements[0];
}
return false;
},
back: function() {
if(!this.empty()){
return elements[cur_element];
}
return false;
},
push: function(var elem){
cur_element++;
elements[cur_element]=elem;
},
pop: function() {
var outcome = elements[del_elem];
delete elements[del_elem];
del_elem++;
return outcome;
}
};
};
remove var from:
push: function(var elem){
In fact, in javascript you don't need (and you mustn't ) to provide the type of a function parameter because it is a statically typed language (see Set type for function parameters?)
Also, to compare with 0, please use === instead of == , check this for reference:
http://dorey.github.io/JavaScript-Equality-Table/?utm_content=buffer4f1b9
So, replace:
return cur_element == 0;
with:
return cur_element === 0;
(PLEASE NOTE: REPLACING == WITH === WAS NOT MANDATORY BUT HIGHLY RECOMMENDED!)
Correct code below:
var queue = function (){
var elements = [];
var cur_element = 0;
var del_elem = 0;
return {
size: function() {
return cur_element-del_elem;
},
empty: function() {
return cur_element === 0;
},
front: function() {
if(!this.empty()){
return elements[0];
}
return false;
},
back: function() {
if(!this.empty()){
return elements[cur_element];
}
return false;
},
push: function(elem){
cur_element++;
elements[cur_element]=elem;
},
pop: function() {
var outcome = elements[del_elem];
delete elements[del_elem];
del_elem++;
return outcome;
}
};
};
http://jsbin.com/tirevipoba/edit?html,js,output
push: function(var elem){
删除var
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