Question

我一直收到错误SyntaxError: Unexpected keyword 'const'. Const declarations are not supported in strict mode.

我认为这是因为我有这样一句话：

    const shouldSet = touches.length === 1;
    if (shouldSet) {
      const { onPanBegin } = this.props;

Answer 1

Update 2015-10-23: as of React Native v0.13.0-rc const is now enabled.

React Native's JavaScript environment is not a browser, instead it uses JavaScriptCore. Anything that isn't supported natively needs to be transformed down to a subset of JS that JavaScriptCore supports, and React Native uses Babel to do that. Here are the transformations that React Native uses (as of 2015-07-31):

ES5

Reserved Words: promise.catch(function() { });

ES6

Arrow functions
Call spread
Classes
Destructuring
Computed Properties
Object Consise Method
Object Short Notation
Rest Params
Template Literals:

ES7

Object Spread
Function Trailing Comma

It is not immediately clear to me why constants aren't included in this list, and it appears that support for overriding it still isn't quite ready:

https://github.com/facebook/react-native/issues/1451

Answer 2

目前在react-native android中不支持<input type="button" onclick="location.href='@Url.Action("MyAction", "MyController", new {})' + '?' + 'newSurname='+getSelectedVersion()"/>关键字，我希望它能在下一版本的react-native中使用。修复是微不足道的，有关详细信息，请查看原点github issue。

Answer 3

你需要得到最新版本的react-native。

pod＆＃39; React＆＃39;，＆＃39; 0.13.0-rc＆＃39;

你如何在react-native中声明'const'？

3 个答案: