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Returns : Function

Think of unitize() like a wrapper around another function, ensuring that the result gets a unit applied, like "px" or "%". For example, perhaps you have a function that only deals with raw numbers like wrap(), but you need the result to get a "px" added to the end. Or maybe the incoming values have units so you need those removed before being fed into your function (wrap() in this example), and then that same unit put back onto the end of the result. No problem!


// get a function that always applies "px" to the result (and strips off any units from the input)
var clamp = gsap.utils.unitize(gsap.utils.clamp(0, 100), "px");

// now the result always gets "px" added:
clamp(132); // "100px"
clamp("-20%"); // "0px" (notice the unit change)
clamp(50); // "50px"

// or use whatever unit is in the input:
var wrap = gsap.utils.unitize(gsap.utils.wrap(0, 100)); // no specific unit is declared in unitize()
wrap("150px"); // 50px
wrap("130%"); // 30%

// another example of forcing a unit like "%":
var map = gsap.utils.unitize(gsap.utils.mapRange(-10, 10, 0, 100), "%");
map(0); // 50%
map("5px"); // 75%

// useful in modifier functions:".class", {
x: 1000,
modifiers: {
//the value fed into this function will have unit - this strips it off to feed in a raw number to wrap() and then slaps "px" onto the result.
x: gsap.utils.unitize(gsap.utils.wrap(0, window.innerWidth), "px"),


  1. function : Function - The function whose result should get the unit applied.
  2. unit : String(optional) - The unit that should always be added to the end of the result. If you omit this parameter, the original unit from the input is applied dynamically.

Note: unitize() strips off any units from the input (using parseFloat()) before passing it along to the function.