When multiple declarators are present in a declaration, we want to insert the constant element inside the declaration rather than placing it before because it may rely on a declarator inside that same declaration.
* Add tests for path type inferers
* Add test for babel-types.valueToNode
* Add tests for babel-types.toKeyAlias
* Add tests for babel-types.toStatement
* Add tests for babel-types.toExpression
* Lint fixes in babel-traverse/test/inference
* babel-traverse: add test to demonstrate repeated identifiers being evaluated to `false`
* fix typo: `value` -> `val`
* path.evaluate: only mark item as resolved if we're confident
As mentioned on the task https://phabricator.babeljs.io/T7179 having
this cache on the AST leads to all sorts of portability and reuse
bugs.
This moves the cache into a clearable WeakMap which will fix the
following:
1. Moving the AST between different babel versions or tools will not
lead into sharing potentially outdated cached information
2. `.clear()` can be called on the cache by a plugin to clear
potentially outdated information. This is helpful when implementing two
seperate pipelines that should not share information.
I think the next step (which is harder, I tried) is to isolate cache and
make it live on a transform or pipeline level state (like the `hub`).
The reason it is hard is because the `babel-traverse` main API -- although
requires the state object to be passed -- not many callers do. To fix
this we should release a patch version that warns about this and fix all
the internal callers. Next couple of releases we can start throwing when
no state is passed (or we can create our own state).
Original PR: https://github.com/babel/babel/pull/2469. Seems this got
lost in the v6 changes.
- - -
Without this, the only way to replace the arrow function is to either
manually override its `node.body`, or duplicate the arrow:
```js
// Old
ArrowFunctionExpression: function (node) {
node.body = t.blockStatement(...);
// Or
return t.ArrowFunctionExpression(
node.params,
t.blockStatement(...),
node.async
);
}
// New
ArrowFunctionExpression: function() {
this.get("body").replaceWith(t.blockStatement(...));
}
```
