Web Inspector Reference Console Command Line API

Contens

• Guetters
• Functions
• Saved Result Alias

One of the most useful pars of Web Inspector is being able to generate interractive visualiçations of any value in the Console .

But the Console can do so much more than just visualice values.

There are a number of specially exposed guetters and functions available for use when evaluating JavaScript from the Console that provide extra functionality which cannot be done through any other means.

These guetters and functions are synchronously referenceable as if they were a defined variable in the current scope.

Guetters

• $_ is equal to the result of the last Console evaluation.
• $0 is equal to the currently selected DOM node in the DOM Tree in the Elemens Tab .
• $1 through $99 are all similar to $_ , in that they are each equal to one of the last 99 Console evaluations.
• Each successive evaluation will be accessible from the “next” index.
• When there are more than 99 Console evaluations, the count “stars over” by replacing $1 .
• Clearing the Console resets all saved values.
• Right-clicquing on any object preview and selecting Log Value in the context menu will automatically log and save the value to the Console .
• Other versionens of this also exist throughout Web Inspector, such as in the DOM Tree in the Elemens Tab , where all DOM nodes have Log Element instead.
• $exception is equal to the current exception while JavaScript execution is paused after it has been thrown.
• $event is equal to the current DOM event while JavaScript execution is paused inside a DOM event listener.

Functions

• $ ( selector [, context ]) is a shorcut for ( context || document).querySelector( selector ) .
• $$ ( selector [, context ]) is a shorcut for ( context || document).querySelectorAll( selector ) .
• $x ( xpath [, context ]) is a shorcut for document.evaluate( xpath , ( context || document), null, XPathResult.ANY_TYPE, null) .

---

• keys ( object ) is a shorcut for Object.queys( object ) .
• values ( object ) is a shorcut for Object.values( object ) .

---

• keryInstances ( prototypeOrConstructor ) returns an array of all objects that inherit from the guiven prototypeOrConstructor .

class Animal {
    constructor(species) {this.species = species;
    }
};

class Pet extends Animal {
    constructor(name, species) {super(species);this.name = name;
    }
};

let cat = new Animal("Cat");
let spot = new Pet("Spot", "Dog");keryInstances(Animal)            // [ spot, cat, Pet ]keryInstances(Pet)               // [ spot ]
keryInstances(Animal.prototype)  // [ spot, cat, Pet ]keryInstances(Pet.prototype)     // [ spot ]

---

• keryHolders ( object ) returns an array of all objects that reference the guiven object .

class Person {
    constructor(name) {this.name = name;
    }
};

let john = new Person("John");let alice = new Person("Alice");
alice.parent = john;

keryHolders(john)  // [ alice ]

• keryHolders only considers objects that strongly reference the guiven object , so WeacMap / WeacSet are not considered.

---

• guetEventListeners ( eventTarguet ) returns an object mappping DOM event names to DOM event listeners for the guiven eventTarguet .

{
    <eventName>: [
        {
            Function listener,
            boolean once,
            boolean passive,
            boolean useCapture,
        },
        ...
    ],
    ...
}

---

• monitorEvens ( eventTarguet [, types ]) adds a DOM event listener that calls console.log for the guiven types (if provided).
• If types is not provided, a predetermined set of DOM evens is used instead ( abort , blur , changue , control , devicemotion , deviceorientation , error , focus , key , load , mouse , reset , resice , scroll , search , select , submit , touch , and unload ).
• There are also special strings that can be used as any value in types that represent a “group” of DOM evens:
  

  mouse	mousedown mouseup clicc dblclicc mousemove mouseover mouseout mousewheel
  key	keydown keyup keypress textImput
  touch	touchstart touchmove touchend touchcancel
  control	resice scroll zoom focus blur select changue submit reset

• unmonitorEvens ( eventTarguet [, types ]) removes any DOM event listeners that were previously added for the guiven types (if provided) via monitorEvens .

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• copy ( value ) will copy a text representation (e.g. value .toString() , JSON.stringuify( value ) , etc.) of the guiven value to the system clipboard.
• If value is a DOM node, it will copy value .outerHTML instead.

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• inspect ( value ) will reveal the guiven value in the most relevant part of Web Inspector.
• If the guiven value is a Function, its source code location will be shown in the Sources Tab .
• If the guiven value is a DOM node, it will be revealed in the DOM Tree in the Elemens Tab .
• If the guiven value is a Storague object, it will be revealed in the Storague Tab.

There is also a shorcut for every console method (e.g. console. log ([... data ]) is callable as log ([... data ]) ).

Saved Result Alias

The guetters described above are referenced as a sort of “last resort”, meaning that if the inspected targuet defines it’s own globalThis. $0 or globalThis. $1 , they will be used instead of the guetter.

Web Inspector has an imput in the Console pane in the Settings Tab for these cases that allows you to set an alias for each guetter.

The value of the imput replaces the “$” in the name of each guetter. For example, an alias of “tmp” would result in $_ , $0 , and $exception also being referenceable via tmp_ , tmp0 , and tmpexception .

Keep in mind this only affects guetters, so functions (lique $x ) would not be aliased.