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TypeScript 3.7 RC & Optional Chaining

https://devblogs.microsoft.com/typescript/announcing-typescript-3-7-rc/#optional-chaining


// Before
if (foo && foo.bar && foo.bar.baz) {
    // ...
}

// After-ish
if (foo?.bar?.baz) {
    // ...
}



upgrade ts

$ npm i -g npm

$ npm -g upgrade typescript

$ tsc -v


ES2020

globalThis

globalThis === window;
// true

globalThis === global;
// true


globalThis =
 Object [global] {
  global: [Circular],
  clearInterval: [Function: clearInterval],
  clearTimeout: [Function: clearTimeout],
  setInterval: [Function: setInterval],
  setTimeout: [Function: setTimeout] {
    [Symbol(nodejs.util.promisify.custom)]: [Function]
  },
  queueMicrotask: [Function: queueMicrotask],
  clearImmediate: [Function: clearImmediate],
  setImmediate: [Function: setImmediate] {
    [Symbol(nodejs.util.promisify.custom)]: [Function]
  }
}
global =
 Object [global] {
  global: [Circular],
  clearInterval: [Function: clearInterval],
  clearTimeout: [Function: clearTimeout],
  setInterval: [Function: setInterval],
  setTimeout: [Function: setTimeout] {
    [Symbol(nodejs.util.promisify.custom)]: [Function]
  },
  queueMicrotask: [Function: queueMicrotask],
  clearImmediate: [Function: clearImmediate],
  setImmediate: [Function: setImmediate] {
    [Symbol(nodejs.util.promisify.custom)]: [Function]
  }
}


https://xie.infoq.cn/article/5887705e51a51af8b2781a8d3


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原文地址:https://www.cnblogs.com/xgqfrms/p/11745541.html