As per me, every variable declared in javascript above functions treat as global. But in my case, i unable to access that variable show undefined. Here is jsfiddle
code:
__getUserByRmId('sun1')
var firstCallFlag = 1;
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
This is because the variable is defined after the function is called.
You can do this. It will work.
var firstCallFlag = 1;
__getUserByRmId('sun1')
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
By the way, hoisting is JavaScript's default behavior of moving all declarations to the top of the current scope. So, something like this should work.
firstCallFlag =1 ;
__getUserByRmId('sun1')
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
var firstCallFlag;
However, JavaScript Initializations are Not Hoisted. Thus, the code like below will consider the variable firstCallFlag undefined.
__getUserByRmId('sun1')
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
var firstCallFlag = 1;
There is a term function and variable hoisting. When you create a function like that and a variable with var, they moved to the top of of all. But the functions are hoisted first before variables. So when you call the function, it sees the function , but doesn't see the variable.
Engine parses your code to this and executes line by line. So it doesn't see the variable.
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
__getUserByRmId('sun1')
var firstCallFlag = 1;
You need to call your function after the variable declaration
var firstCallFlag = 1;
__getUserByRmId('sun1');
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
} Call the function after declaring the variable. Function will hoist first and then the variables.
var firstCallFlag = 1;
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
__getUserByRmId('sun1');If you still want to work with the same pattern of approach without declaring the variable on top of function call, then you should have a timeout call like this:
_getUserByRmId('sun1');
var firstCallFlag = 1;
function __getUserByRmId(rmId) {
setTimeout(function(){
console.log(firstCallFlag);
},1);
}
var firstCallFlag = 1;
function __getUserByRmId(rmId) {
console.log(firstCallFlag);
}
__getUserByRmId('sun1');Its beacuse you have to define the variable "firstCallFlag " first and then call the function __getUserByRmId('sun1');....variable hoisting in javascript
