i want to run a function, inside another function dynamically...
let say :
<script>
var x = function(r,s){
r(s);
}
var a = function(item){
alert("aA");
}
var b = function(item){
alert("bB");
}
</script>
is this possible? i take "r" from function x's argument as a function name, and i want to run it.
if r=a, then it will trigger function a()
and if r=b, function b triggered instead...
how could i do that?
You could simply test r and call each function as needed.
if (r === 'a') {
a(s);
} else if (r === 'b') {
b(s);
}
Or, if you have many functions for this or don't always know them all ahead of time, you can organize them in an Object and use bracket operators to treat r as a key name to access them:
var commands = {
a: function(item){
alert("aA");
},
b: function(item){
alert("bB");
}
};
var x = function (r, s) {
var command = commands[r];
if (typeof command === 'function') {
command(s);
}
};
x('a', 'foo'); // alerts `aA`
Or, even just pass a and b as the arguments themselves with your current definition of x().
x(a, 'foo'); // calls `a` as `r`, passing 'foo' along
By passing the name of the function as the first parameter to x when calling it.
x(a, {}); // alert("aA");
x(b, {}); // alert("bB");
Note that you're passing the reference to the function, not a string. This is because functions in JavaScript are objects and are passed by reference, not by value. So var a = function() {...}; actually means that variable a holds a reference to the function.
you mean like:
var x = function(r,s){
window[r](s);
}
var a = function(item){
alert("aA");
}
var b = function(item){
alert("bB:" + item);
}
x('b', 'test');
