fix: require Node.js 6+ for all packages

[DanielRuf]

Summary

Changes in Jest packages require at least Node.js 6.5+ so there is also no compatibility with older releases of Node.js 6.

Motivation: Node.js 4 support was officially dropped in Jest 22 and we test only 6, 8 and 10 so it makes sense to enforce node >= 6 on all packages to prevent breaking builds due to incompatible Node.js versions as this is a hard breaking change.

See https://jestjs.io/blog/2017/12/18/jest-22

See #7253

Test plan

[SimenB]

We already have it, it seems: https://github.com/facebook/jest/blob/319329f7942ed33f0be706a19a2b23d08eac0ea0/packages/jest/package.json#L14
https://github.com/facebook/jest/blob/319329f7942ed33f0be706a19a2b23d08eac0ea0/packages/jest-cli/package.json#L48

What package did you install that did not warn?
We can update it to a newer version of 6 if array.includes was not in 6.0.0, but I'm unable to figure out what version it was introduced in...

[DanielRuf]

See http://kangax.github.io/compat-table/es2016plus/#node6_5 for Array.prototype.includes.

It was in jest-validate with blacklist.includes (and possibly more as there is also the spread operator).

[DanielRuf]

Well, but in our case it did not warn that Node.js 6 is required for Jest. See https://travis-ci.org/docker/kitematic/builds/443616745#L475

https://node.green/#ES2016-features-Array-prototype-includes

[SimenB]

We might want to add it to all packages, then. Didn't think about the case where people use the other parts of jest, silly to overlook.

Well, but in our case it did not warn that Node.js 6 is required for Jest.

That seems like an npm bug. Maybe because it's fetched from cache?

See http://kangax.github.io/compat-table/es2016plus/#node6_5 for Array.prototype.includes.

Yes, but it doesn't mention anything about 6.0.0 not having it.

Node 6.0.0 has it:

[DanielRuf]

We might want to add it to all packages, then. Didn't think about the case where people use the other parts of jest, silly to overlook.

What can I do here to help?

That seems like an npm bug. Maybe because it's fetched from cache?

Not sure as this is a very old npm version which was shipped with Node.js 4.

[SimenB]

What can I do here to help?

If you update all packages/*/package.json to include the engine part, that'd be awesome 🙂

That seems like an npm bug. Maybe because it's fetched from cache?

Not sure as this is a very old npm version which was shipped with Node.js 4.

🤷‍♂️ Not much we can do here though, as we have had that engine field since #4769 was merged (2 days less than a year ago).

[DanielRuf]

Ok I'll change it to >= 6 and update the other package.json files too to ensure that all packages enforce the same minimum requirement so we can assure that no old Node.js release line tries to run unsupported code.

So it seems the table is not exact.
Mh, is there a better table just for Node.js? https://node.green/#ES2016-features-Array-prototype-includes is not more helpful as it only shows 6.4.0+ for 6.x.

Not sure if exact:

[codecov-io]

Codecov Report

Merging #7258 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #7258   +/-   ##
=======================================
  Coverage   66.55%   66.55%           
=======================================
  Files         237      237           
  Lines        9317     9317           
  Branches        4        3    -1     
=======================================
  Hits         6201     6201           
  Misses       3115     3115           
  Partials        1        1

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[SimenB]

Could you update the changelog as well?

[DanielRuf]

Could you update the changelog as well?

How exactly? I never did this in this repo before so I am open to any code suggestions (and it is open for edits by maintainers).

https://blog.github.com/2018-10-16-future-of-software/#suggested-changes-public-beta

[SimenB]

Add an entry under "Chore" here: https://github.com/facebook/jest/blob/master/CHANGELOG.md

[DanielRuf]

Add an entry under "Chore" here: /CHANGELOG.md@master

Done.

[SimenB]

Thanks!

[github-actions]

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