Pollyfills in JavaScript
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The document explains the concept of polyfills in JavaScript, which are code pieces used to add modern functionality to older browsers lacking native support. It provides examples of polyfills for the 'startsWith' method and for retrieving values from objects. The document also advises on loading polyfills only when necessary and incorporating them as project dependencies.
![Another example of a polyfill is for get values
from Object.
if (!Object.prototype.values) {
Object.prototype.values = function (obj) {
var values = Object.keys(obj).map(function(e) {
return obj[e];
});
return values;
};
}
Now you have the power to hack the browser to
support the missing features.
Load Polyfills Only When Needed. We can include
polyfills in a separate file, we can add it as a
dependency in projects.](https://image.slidesharecdn.com/r7waicyit0wuhf0fopnu-signature-47bce0270a270cdae3e38ca2719aef19d77a1476fe1c8e8aa3d6dec8c663dc65-poli-200609035404/85/Pollyfills-in-JavaScript-3-320.jpg)
Pollyfills in JavaScript
- 2. JavaScript is notorious for having cross-browser compatibility issues. A polyfill is a piece of code (usually JavaScript on the Web) used to provide modern functionality on older browsers that do not natively support it. One example of a polyfill is the code below which is a polyfill for the new ES6 String method startsWith(): if (!String.prototype.startsWith) { String.prototype.startsWith = function (searchString, position) { position = position || 0; return this.substr(position, searchString.length) === searchString; }; }
- 3. Another example of a polyfill is for get values from Object. if (!Object.prototype.values) { Object.prototype.values = function (obj) { var values = Object.keys(obj).map(function(e) { return obj[e]; }); return values; }; } Now you have the power to hack the browser to support the missing features. Load Polyfills Only When Needed. We can include polyfills in a separate file, we can add it as a dependency in projects.