fix(exports): node 13.0-13.6 require a string fallback

[ljharb]

package.json’s "engines" field claims cliui supports node >= 6; node v13.0-v13.6 are included in this semver range. This change is required to be able to require() from escalade successfully in these versions.

See yargs/yargs#1776

I've manually tested this; it fixes the bug. Since the behavior can only be observed by installing escalade into a node_modules folder and then trying to require it, it's exceedingly difficult to test in CI.

[codecov-io]

Codecov Report

Merging #6 into master will not change coverage.
The diff coverage is n/a.

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##            master        #6   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files            2         2           
  Lines           20        20           
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  Hits            20        20           

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[lukeed]

Hey,

I checked out the imports locally. TIL!

However, why is it pointing to the CommonJS files? In Node 13.0-13.6, export is supported.
I know this means require wouldn't work, but still. Sending the CommonJS file would make something like a kleur/colors module (with named exports only) fail; for example:

// Node 13.4, with this PR's approach
import * as colors from 'kleur/colors';
//=> { default: { red, blue, ... } }

import { red } from 'kleur/colors';
// SyntaxError: The requested module 'kleur/colors' does not provide an export named 'red'

// Node 14.x
import * as colors from 'kleur/colors';
//=> { red, blue, ... }

import { red } from 'kleur/colors';
// OK

So it'd skip the immediate module-loader error, but it either requires an interop-check in all places or fails silently because the exports don't align.

[ljharb]

You can't require ESM files, and the bug I'm trying to fix is being able to require yargs (which requires escalade) in node v13.0-v13.6.

It's impossible to support both CJS and ESM in those versions, and since CJS can be both required and imported, that's the only approach that makes sense imo.

[ljharb]

In other words, I think CJS is a far, far more important consumer than ESM, because most node users aren't using ESM yet - and because for escalade to be consumed as ESM, everything that consumes it must also consume with ESM. Being ESM-only is viral - being CJS-only is not.

[lukeed]

Gotcha :) While certainly not ideal, I agree it's the safer/wider support range.
In some future version, the engines list can outlaw those Node versions... but really, I wish there was some way to ban Node 13.0-13.6 outright (or maybe all odd, non-latest versions in general). This range continually causes headache for ESM adoption and there's just zero reason to be using one of these Node versions.

Anyway, thanks!

[lukeed]

Published escalade@3.1.1

[ljharb]

Thank you!