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102 lines
3.0 KiB
102 lines
3.0 KiB
/** |
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* @callback EventCallback |
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* @param {string | Error | null} context |
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* @returns {void} |
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*/ |
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/** |
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* @callback EventHandler |
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* @param {Event} event |
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* @returns {void} |
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*/ |
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/** |
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* A function that creates an event handler for the `error` event. |
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* @param {EventCallback} callback A function called to handle the error context. |
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* @returns {EventHandler} A handler for the `error` event. |
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*/ |
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function createErrorHandler(callback) { |
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return function errorHandler(event) { |
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if (!event || !event.error) { |
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return callback(null); |
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} |
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if (event.error instanceof Error) { |
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return callback(event.error); |
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} |
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// A non-error was thrown, we don't have a trace. :( |
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// Look in your browser's devtools for more information |
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return callback(new Error(event.error)); |
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}; |
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} |
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/** |
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* A function that creates an event handler for the `unhandledrejection` event. |
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* @param {EventCallback} callback A function called to handle the error context. |
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* @returns {EventHandler} A handler for the `unhandledrejection` event. |
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*/ |
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function createRejectionHandler(callback) { |
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return function rejectionHandler(event) { |
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if (!event || !event.reason) { |
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return callback(new Error('Unknown')); |
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} |
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if (event.reason instanceof Error) { |
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return callback(event.reason); |
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} |
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// A non-error was rejected, we don't have a trace :( |
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// Look in your browser's devtools for more information |
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return callback(new Error(event.reason)); |
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}; |
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} |
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/** |
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* Creates a handler that registers an EventListener on window for a valid type |
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* and calls a callback when the event fires. |
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* @param {string} eventType A valid DOM event type. |
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* @param {function(EventCallback): EventHandler} createHandler A function that creates an event handler. |
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* @returns {register} A function that registers the EventListener given a callback. |
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*/ |
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function createWindowEventHandler(eventType, createHandler) { |
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/** |
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* @type {EventHandler | null} A cached event handler function. |
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*/ |
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let eventHandler = null; |
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/** |
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* Unregisters an EventListener if it has been registered. |
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* @returns {void} |
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*/ |
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function unregister() { |
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if (eventHandler === null) { |
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return; |
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} |
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window.removeEventListener(eventType, eventHandler); |
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eventHandler = null; |
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} |
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/** |
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* Registers an EventListener if it hasn't been registered. |
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* @param {EventCallback} callback A function called after the event handler to handle its context. |
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* @returns {unregister | void} A function to unregister the registered EventListener if registration is performed. |
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*/ |
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function register(callback) { |
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if (eventHandler !== null) { |
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return; |
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} |
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eventHandler = createHandler(callback); |
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window.addEventListener(eventType, eventHandler); |
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return unregister; |
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} |
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return register; |
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} |
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const handleError = createWindowEventHandler('error', createErrorHandler); |
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const handleUnhandledRejection = createWindowEventHandler( |
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'unhandledrejection', |
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createRejectionHandler |
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); |
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module.exports = { |
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handleError: handleError, |
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handleUnhandledRejection: handleUnhandledRejection, |
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};
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