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JS Bin // source https://jsbin.com/kuhukal
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>JS Bin</title>
</head>
<body>
<script id="jsbin-javascript">
// Note: ES6 code, works in modern browsers
const makeAjaxRequest = () => { /* production code */ };
// say we have a User class somewhere
class User {
trackAction(action, category) {
makeAjaxRequest({ action, category, isLoggedIn: this.loggedIn });
}
}
const loggedInUser = new User();
// elsewhere in the code..
loggedInUser.fullName = 'Bob Jenkins';
loggedInUser.id = 184643;
loggedInUser.trackAction('add-product', 'shoes');
const originalFn = loggedInUser.trackAction;
// print the arguments of the function to the console
// yet still call original function with right context and arguments
loggedInUser.trackAction = function() {
// convert function arguments to array
const args = Array.prototype.slice.call(arguments);
console.log('trackAction called for %s with the following arguments: %s.', this.fullName, args.join(', '));
// being a good citizen means returning the result of the original function
// and making sure it is executed with the correct context and arguments
return originalFn.apply(this, args);
};
loggedInUser.trackAction('add-product', 'shoes');
// trackAction called for Bob Jenkins with the following arguments: add-product, shoes.
</script>
<script id="jsbin-source-javascript" type="text/javascript">// Note: ES6 code, works in modern browsers
const makeAjaxRequest = () => { /* production code */ };
// say we have a User class somewhere
class User {
trackAction(action, category) {
makeAjaxRequest({ action, category, isLoggedIn: this.loggedIn });
}
}
const loggedInUser = new User();
// elsewhere in the code..
loggedInUser.fullName = 'Bob Jenkins';
loggedInUser.id = 184643;
loggedInUser.trackAction('add-product', 'shoes');
const originalFn = loggedInUser.trackAction;
// print the arguments of the function to the console
// yet still call original function with right context and arguments
loggedInUser.trackAction = function() {
// convert function arguments to array
const args = Array.prototype.slice.call(arguments);
console.log('trackAction called for %s with the following arguments: %s.', this.fullName, args.join(', '));
// being a good citizen means returning the result of the original function
// and making sure it is executed with the correct context and arguments
return originalFn.apply(this, args);
};
loggedInUser.trackAction('add-product', 'shoes');
// trackAction called for Bob Jenkins with the following arguments: add-product, shoes.</script></body>
</html>
// Note: ES6 code, works in modern browsers
const makeAjaxRequest = () => { /* production code */ };
// say we have a User class somewhere
class User {
trackAction(action, category) {
makeAjaxRequest({ action, category, isLoggedIn: this.loggedIn });
}
}
const loggedInUser = new User();
// elsewhere in the code..
loggedInUser.fullName = 'Bob Jenkins';
loggedInUser.id = 184643;
loggedInUser.trackAction('add-product', 'shoes');
const originalFn = loggedInUser.trackAction;
// print the arguments of the function to the console
// yet still call original function with right context and arguments
loggedInUser.trackAction = function() {
// convert function arguments to array
const args = Array.prototype.slice.call(arguments);
console.log('trackAction called for %s with the following arguments: %s.', this.fullName, args.join(', '));
// being a good citizen means returning the result of the original function
// and making sure it is executed with the correct context and arguments
return originalFn.apply(this, args);
};
loggedInUser.trackAction('add-product', 'shoes');
// trackAction called for Bob Jenkins with the following arguments: add-product, shoes.
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