The JavaScript exception "rest parameter may not have a default" occurs when a rest parameter has a default value. Because the rest parameter always creates an array, the default value would never apply.... Examples Invalid cases js function doSomething(...args...args = []) {} Valid cases js function doSomething(...args) { // args...
The JavaScript exception "return not in function" occurs when a return statement is called outside of a function....Examples Missing curly braces js function cheer(score) { if (score...statement. Correct would be: js function cheer(score) { if (score...
The JavaScript exception "missing } after property list" occurs when there is a mistake
in the object initializer syntax somewhere.
Might be in fact a missing curly bracket, but could also be a missing comma....your object initializer code: js const obj = { a: 1, b: { myProp:...2 } c: 3 }; Correct would be: js const obj = { a: 1, b: { myProp:...
Learn about the HTMLMediaElement.addTextTrack() method, including its syntax, code examples, specifications, and browser compatibility.... Syntax js addTextTrack(kind) addTextTrack(kind...and adds a new VTTCue to that. js const video = document.querySelector("video");...
Learn about the online event, including its type and syntax, code examples, specifications, and browser compatibility.... js addEventListener("online", (event)...HTMLFrameSetElement SVGSVGElement Examples js // addEventListener version window...
The JavaScript exception "incomplete quantifier in regular expression" occurs when a regular expression pattern contains a {, but it does not start a valid quantifier.... Examples Invalid cases js /1{/u; /1{a}/u; /1{}/u; /1{1...3}/u; /1{1, 2}/u; Valid cases js /1{1}/u; /1{1,}/u; /1{1,2}/u;...
Working with the clipboard in extensions is transitioning from the Web API document.execCommand method (which is deprecated) to the navigator.clipboard method....query() : js navigator.permissions.query({...and writes it to the clipboard: js function updateClipboard(newClip)...
A shallow copy of an object is a copy whose properties share the same references (point to the same underlying values) as those of the source object from which the copy was made. As a result, when you change either the source or the copy, you may also cause the other object to change too. That behavior contrasts with the behavior of a deep copy, in which the source and copy are completely independent.... js const ingredientsList = ["noodles"...will be visible in both objects. js ingredientsListCopy[1].list =...
The JavaScript exception "Iterator constructor can't be used directly" or "AsyncIterator constructor can't be used directly" occurs when you try to use the Iterator() or AsyncIterator() constructors directly to create instances. These constructors are abstract classes and should only be inherited from....Invalid cases js new Iterator(); Valid cases js class MyIterator...
Learn about the HTMLElement.popover property, including its type, code examples, specifications, and browser compatibility....feature detect the Popover API : js function supportsPopover() {...up a popover programmatically js const popover = document.get...