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This article mainly explains "the example usage of Promise exception capture in javascript". The explanation in this article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "the example usage of Promise exception catch in javascript".

1. In the then method of promise, we have automatically helped us with the try catch callback function.

Promise.prototype.then = function (cb) {try {cb ()} catch (e) {/ / todo reject (e)}}

2. The exception thrown in the then method will be caught by the second parameter of the next cascading then method.

Promise.prototype.done = function (resolve, reject) {this.then (resolve, reject) .catch (function (reason) {setTimeout (() = > {throw reason;}, 0);});}

If the last then has an exception, you can add a done method, which does not return a promise object, so it cannot be cascaded later. The done method eventually throws the exception globally so that the thread can be caught or interrupted by the global exception handler. This is also the best practice strategy for promise.

Thank you for your reading. The above is the content of "instance usage of Promise exception capture in javascript". After the study of this article, I believe you have a deeper understanding of the instance usage of Promise exception catch in javascript, and the specific usage needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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