Typescript `import =` is not supported.

[rosskevin]

Choose one: is this a bug report or feature request?
Bug (or feature - because typescript support is new)

Input Code

import debounce = require('lodash/debounce')

Babel/Babylon Configuration (.babelrc, package.json, cli command)

{
  "presets": [
    "@babel/preset-typescript",
    "@babel/preset-env",
    "@babel/preset-stage-1",
    "@babel/preset-react"
  ]
} 

Expected Behavior

From https://www.typescriptlang.org/docs/handbook/modules.html#export--and-import--require

When importing a module using export =, TypeScript-specific import module = require("module") must be used to import the module.

Current Behavior

SyntaxError: src/transitions/Slide.tsx: `import =` is not supported.

    at File.buildCodeFrameError (/Users/kross/projects/material-ui/node_modules/@babel/core/lib/transformation/file/file.js:209:12)
    at NodePath.buildCodeFrameError (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/path/index.js:155:26)
    at PluginPass.TSImportEqualsDeclaration (/Users/kross/projects/material-ui/node_modules/@babel/plugin-transform-typescript/lib/index.js:208:20)
    at newFn (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/visitors.js:223:21)
    at NodePath._call (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/path/context.js:64:19)
    at NodePath.call (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/path/context.js:38:17)
    at NodePath.visit (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/path/context.js:99:12)
    at TraversalContext.visitQueue (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/context.js:139:18)
    at TraversalContext.visitMultiple (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/context.js:93:17)
    at TraversalContext.visit (/Users/kross/projects/material-ui/node_modules/@babel/traverse/lib/context.js:178:19)

Possible Solution

One idea would be that since this is a typescript only concept, and babel handles the other syntax well, just convert

import debounce = require('lodash/debounce')

to

import debounce from 'lodash/debounce'

Context

Cannot use babel 7 directly without tsc preprocessing.

Your Environment

software	version(s)
Babel	@babel/core@7.0.0-beta.35
node	9.3.0
Operating System	OSX

[babel-bot]

Hey @rosskevin! We really appreciate you taking the time to report an issue. The collaborators
on this project attempt to help as many people as possible, but we're a limited number of volunteers,
so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack
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[hzoo]

This is already documented as a caveat which is why the error message import = is not supported

https://github.com/babel/babel/blob/master/packages/babel-plugin-transform-typescript/README.md#babelplugin-transform-typescript

The TS team made the original PR, unless we think it's worth adding this behavior still, someone would need to make a case/PR (needs a parser change + transform change) @Andy-MS

Like you suggested, when using babel it's better to use a default import. This is supported in TypeScript by using the --allowSyntheticDefaultImports flag.
(Created microsoft/TypeScript-Handbook#700)

[rosskevin]

Thanks, I used --allowSyntheticDefaultImports a bit reluctantly, it has been useful in finding errors but understand that the fix for that usage may be painful to implement here.

[loganfsmyth]

Should we expand that error message with a bit more info so users know what to do next?

[rosskevin]

I think expanding the message with @Andy-MS's link/text would be a good idea.

[hzoo]

Yes, definetely

[loganfsmyth]

Filed: #7067