这个JS代码片做了什么？ `“发展”！=='生产'

Question

It's all over this react.js file :

if ("development" !== 'production') {
  var typeofSpec = typeof spec;
  var isMixinValid = typeofSpec === 'object' && spec !== null;

  "development" !== 'production' ? warning(isMixinValid, '%s: You\'re attempting to include a mixin that is either null ' + 'or not an object. Check the mixins included by the component, ' + 'as well as any mixins they include themselves. ' + 'Expected object but got %s.', Constructor.displayName || 'ReactClass', spec === null ? null : typeofSpec) : void 0;
}

When would it ever be false? In what way is it useful? Was it autogenerated?

Answer 1

The purpose of "development" !== 'production' is to enable development mode. The reason it is done this way is so that the block is removed from the production build during minification.

When building for production, "production" !== "production" can never be true , so the block is removed by the minifier.