The JavaScript exception "missing = in const declaration" occurs when a const
declaration was not given a value in the same statement (like
const RED_FLAG;). You need to provide one
(const RED_FLAG = "#ff0").... This throws: js const COLUMNS; // SyntaxError:...statement in which it's declared: js const COLUMNS = 80; const , let...
The JavaScript exception "duplicate formal argument x" or "duplicate argument names not allowed in this context" occurs when a function creates two or more parameter bindings with the same name, and the function is not a non-strict function with only simple parameters.... Examples Invalid cases js "use strict"; function add(x...duplicate formal argument x } js function doSomething(name, {...
Learn about the XRLightProbe interface, including its properties and methods, code examples, specifications, and browser compatibility.... js const lightProbe = await xrSession...get a light probe for a pose. js const probePose = xrFrame.getPose(lightProbe...
The class keyword can be used to define a class inside an expression.... Try it Syntax js class { // class body } class...refer to using the variable Foo . js const Foo = class { constructor()...
The JavaScript exception "reduce of empty array with no initial value" occurs when a
reduce function is used.... js const ints = [0, -1, -2, -3,...number of elements in a list: js const names = document.getEl...
The JavaScript exception "reference to undeclared private field or method #x" occurs when a private name is used, but this private name is not declared in the class scope.... js class MyClass { doSomething()...an undeclared private field. js class MyClass { doSomething()...
Learn about the playing event, including its type and syntax, code examples, specifications, and browser compatibility.... js addEventListener("playing", (event)...firing. Using addEventListener() : js const video = document.querySelector("video");...
Learn about the seeked event, including its type and syntax, code examples, specifications, and browser compatibility.... js addEventListener("seeked", (event)...firing. Using addEventListener() : js const video = document.querySelector("video");...
Learn about the removetrack event, including its type, syntax, and properties, code examples, specifications, and browser compatibility.... js addEventListener("removetrack"...Examples Using addEventListener() : js const videoElement = document...
Static initialization blocks are declared within a class. It contains statements to be evaluated during class initialization. This permits more flexible initialization logic than static properties, such as using try...catch or setting multiple fields from a single value. Initialization is performed in the context of the current class declaration, with access to private state, which allows the class to share information of its private properties with other classes or functions declared in the same scope (analogous to "friend" classes in C++).... Try it Syntax js class ClassWithSIB { static {...after the class declaration: js class MyClass { static init()...