Inspector Bootstrap Script.js

/*
 * The Inspector Bootstrap Script is guaranteed to be the first script evaluated in any page, as well as any sub-frames.
 * It is evaluated immediately after the global object is created, before any other content has loaded.
 * 
 * Modifications made here will take effect on the next load of any page or sub-frame.
 * The contents and enabled state will be preserved across Web Inspector sessions.
 * 
 * Some examples of ways to use this script include (but are not limited to):
 *  - overriding built-in functions to log call traces or add `debugger` statements
 *  - ensuring that common debugging functions are available on every page via the Console
 * 
 * More information is available at <https://webkit.org/web-inspector/inspector-bootstrap-script/>.
 */

(function() {
    function swizzleProperty(object, name, options) {
        if (!object)
            return;

        let originalProperty = Object.getOwnPropertyDescriptor(object.prototype, name);
        if (!originalProperty) {
            console.log(`Failed to swizzle property ${name}`);
            return;
        }
        Object.defineProperty(object.prototype, name, {
            configurable: originalProperty.configurable,
            get: function() {
                let result = originalProperty.get.apply(this, arguments);
                if (options.get)
                    options.get.apply(this, [result]);
                return result;
            },
            set: function() {
                if (options.set)
                    options.set.apply(this, arguments);
                return originalProperty.set.apply(this, arguments);
            }
        });
    }

    function swizzleFunction(object, name, func) {
        if (!object)
            return;

        if (!object[name]) {
            console.log(`Failed to swizzle function ${name}`);
            return;
        }

        let originalFunction = object[name];
        object[name] = function() {
            return func.apply(this, [originalFunction, arguments]);
        };
    }

    swizzleFunction(HTMLMediaElement.prototype, 'play', function(originalPlay) {
        console.log('JER: play()');
        let mediaElement = this;
        let playPromise = originalPlay.apply(this);
        playPromise.then(() => {
            console.log('JER: play() resolved');
        }).catch(error => {
            console.log(`JER: play() rejected with ${error}`);
        });
        return playPromise;
    });

    swizzleFunction(HTMLMediaElement.prototype, 'pause', function(originalPause) {
        console.log('JER: pause()');
        return originalPause.apply(this);
    });

    swizzleFunction(HTMLMediaElement.prototype, 'load', function(originalLoad) {
        console.log('JER: load()');
        return originalLoad.apply(this);
    });

    swizzleFunction(HTMLMediaElement.prototype, 'setAttribute', function(originalSetAttribute, originalArguments) {
        let key = originalArguments[0] ?? null;
        let value = originalArguments[1] ?? null;
        console.log(`JER: setAttribute(${key}, ${value})`);
        return originalSetAttribute.apply(this, originalArguments);
    });

    swizzleFunction(HTMLMediaElement.prototype, 'canPlayType', function(originalCanPlayType, originalArguments) {
        let answer = originalCanPlayType.apply(this, originalArguments);
        let type = originalArguments[0] ?? null;
        if (type.includes('av01')) debugger;
        console.log(`JER: canPlayType(${type} == "${answer}")`);
        return answer;
    });

    swizzleProperty(HTMLMediaElement, 'src', {
        set: url => console.log(`JER: set url("${url}")`)
    });

    swizzleFunction(MediaCapabilities.prototype, 'decodingInfo', function(origininalDecodingInfo, originalArguments) {
        let configuration = originalArguments[0] ?? null;
        console.log(`JER: decodingInfo(${JSON.stringify(configuration)})`);
        let promise = origininalDecodingInfo.apply(this, originalArguments);
        promise.then((results) => {
            console.log(`JER: decodingInfo() resolved: ${JSON.stringify(results)}`);
        }).catch(error => {
            console.log(`JER: decodingInfo() rejected with ${error}`);
        });
        return promise;
    });

    swizzleFunction(MediaSource, 'isTypeSupported', function(originalIsTypeSupported, originalArguments) {
        let result = originalIsTypeSupported.apply(this, originalArguments);
        console.log(`JER: isTypeSupported(${originalArguments[0]}) == ${result}`);
        return result;
    });

    swizzleFunction(Document.prototype, 'exitPictureInPicture', function(originalExitPictureInPicture, originalArguments) {
        console.log(`JER: exitPictureInPicture`);
        let promise = originalExitPictureInPicture.apply(this, originalArguments);
        promise.then((results) => {
            console.log(`JER: exitPictureInPicture() resolved`);
        }).catch(error => {
            console.log(`JER: exitPictureInPicture() rejected with ${error}`);
        });
        return result;
    });

//     swizzleProperty(HTMLVideoElement, 'videoWidth', {
//         get: width => console.log(`JER: videoWidth - ${width}`)
//     });

//     swizzleProperty(HTMLVideoElement, 'videoHeight', {
//         get: height => console.log(`JER: videoHeight - ${height}`)
//     });

    swizzleProperty(TextTrack, 'mode', {
        set: mode => console.log(`JER: set track mode("${mode}")`) 
    });

//     let originalCreateObjectURL = URL.createObjectURL;
//     URL.createObjectURL = function(param) {
//         console.log('JER: createObjectURL(:)');
//         param = param.slice(0, param.size, "application/x-mpegURL")
//         return originalCreateObjectURL.apply(this, [param]);
//     }

//     let originalAppendChild = Node.prototype.appendChild;
//     Node.prototype.appendChild = function(child) {
//         console.log(`JER: appendChild(${child})`);

//         return originalAppendChild.apply(this, [child]);
//     };

}());