promises-aplus-robin

promises-aplus-robin is a lightweight Promises/A+ implementation that is able to detect circular thenable chain. Except for the features defined in the Promises/A+ Standard, more features can be found in the extended version.

Supported Features

• Promise/A+ standard
• detecting thenable cycle
• MyPromise.prototype.catch
• MyPromise.prototype.finally
• MyPromise.resolve
• MyPromise.reject
• MyPromise.all
• MyPromise.race
• ......

Versions

• raw version: promises-aplus-robin.js
• annotated version: promises-aplus-robin-annotated.js
• extended version: promises-aplus-robin-extended.js
• hack version: promises-aplus-robin-hack.js

The extended version is used for supporting some features that is excluded in Promises/A+ standard but can be found in modern browsers.

The hack version is used for adapting the following case. The explanation can be found at 我以为我很懂Promise，直到我开始实现Promise/A+规范.

Promise.resolve().then(() => {
    console.log(0);
    return Promise.resolve(4);
}).then((res) => {
    console.log(res)
})

Promise.resolve().then(() => {
    console.log(1);
}).then(() => {
    console.log(2);
}).then(() => {
    console.log(3);
}).then(() => {
    console.log(5);
}).then(() =>{
    console.log(6);
})

Testing

The implementation of Promise/A+ can be tested by promises-tests.

npm run test