Angular CLI compiler requires older Typescript

[jtsom]

Bug Report or Feature Request (mark with an x)

- [x] bug report -> please search issues before submitting
- [ ] feature request

Versions.

@angular/cli: 1.4.0
node: 8.4.0
os: darwin x64
@angular/animations: 4.3.6
@angular/cdk: 2.0.0-beta.10
@angular/common: 4.3.6
@angular/compiler: 4.3.6
@angular/core: 4.3.6
@angular/forms: 4.3.6
@angular/http: 4.3.6
@angular/material: 2.0.0-beta.10
@angular/platform-browser: 4.3.6
@angular/platform-browser-dynamic: 4.3.6
@angular/router: 4.3.6
@angular/cli: 1.4.0
@angular/compiler-cli: 4.3.6
@angular/language-service: 4.3.6
typescript: 2.5.2

Repro steps.

Start up app with ng serve and this message is displayed:

@angular/compiler-cli@4.3.6 requires typescript@'>=2.1.0 <2.4.0' but 2.5.2 was found instead.
Using this version can result in undefined behaviour and difficult to debug problems.

Please run the following command to install a compatible version of TypeScript.

    npm install typescript@'>=2.1.0 <2.4.0'

To disable this warning run "ng set --global warnings.typescriptMismatch=false".

[kuncevic]

Based on that commit it should allow 2.5+ but I have same issue even with 2.4.2 and angular 4.3.6

UPDATE: Based on that sounds like typescript: '>=2.4.0 <2.6.0' required angular compiler '>=5.0.0 <6.0.0'

[karser]

Newly created project with angular-cli@1.4.0 requires typescript@~2.3.3

[kondi]

Is this requirement valid? My project looks fine with typescript@2.4.2 and I was planning to go for 2.5.x but now I am not sure if it is a good idea.

[kondi]

Anyway it would be good if @angular/compiler-cli would define the correct peer dependency here: https://github.com/angular/angular/blob/4.4.x/packages/compiler-cli/package.json#L17. Not everybody is using angular-cli. I can understand the safety check, but I am not sure the matrix linked by kuncevic should be the correct place to specify the requirements.

[jtsom]

There were no indications that this restriction would be implemented. The only thing I updated in my project was the CLI. The @angular/compiler-cli@4.3.6 has no problems previously.

[filipesilva]

These versions shown in the warning are the ones recommended by the Angular team.

A lot of bugs that are reported are actually the result of using incompatible versions, and it is not clear at all what these versions are. This is not a new restriction: incompatible versions have caused problems for a while now.

It is true that other typescript versions may work in your particular project - but we cannot guarantee they will work. That is why we show a warning now (but not an error).

It became more important to alert users to what the recommended versions are because Angular version 5 is coming out and it has its own recommend set of typescript versions.

There are two factors preventing simply adding a strict dependency:

• the CLI must support Angular versions 2, 4, and 5
• Angular itself does not have a dependency/peer dependency on typescript

So it was better to show a warning than to prevent usage of other typescript versions. If you feel confident that your project should work with other versions of typescript, you can disable the warning. This is useful when using versions of libraries that specifically need typescript of a certain version for compilation to be successful.

[fmorriso]

@filipesilva : Thanks for the high-level explanation.

For those of us who wish to "scout ahead" using TypeScript versions beyond what is recommended, is there a place where any known issues (with or without a fix/work-around) have been documented?

[xnnkmd]

@filipesilva See also #7678 which would help a lot related to the warning.

[TitaneBoy]

Hi guys...
Having the same issue with @angular/compiler-cli@4.4.3

Node: 8.4.0
Typescript: 2.5.2

But as we can see in the package.json of angular/compiler-cli, it saids, in its peerDependencies, that it needs typescript ^2.0.2, and typescript@2.5.2 should meet this requirement

[dherges]

Maybe the dependencies on typescript should be a peerDependencies?

A CLI project may now cause more confusion:

- node_modules
  |- @angular
     |- cli
        |- node_modules
           |- typescript # <- 2.5.x (from cli package.json >=2.0.0 < 2.6.0)
  |- typescript # <- 2.4.x (from package.json)
package.json