fix($core): isProd is undefined in ready hook

[meteorlxy]

Summary

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe:

If changing the UI of default theme, please provide the before/after screenshot:

Does this PR introduce a breaking change? (check one)

• Yes
• No

Other information:

Currently, we set isProd in app.dev() and app.build().

vuepress/packages/@vuepress/core/lib/node/App.js

Lines 491 to 497 in 1a930dc

	async build () {
	this.isProd = true
	this.buildProcess = new BuildProcess(this)
	await this.buildProcess.process()
	await this.buildProcess.render()
	return this
	}

As app.process() runs before app.dev() and app.build(), we cannot get isProd in app.process().

vuepress/packages/@vuepress/core/lib/index.js

Lines 18 to 22 in 1a930dc

	async function build (options) {
	const app = createApp(options)
	await app.process()
	return app.build()
	}

However, ready() hook is applied in app.process(), in which we may need isProd.

vuepress/packages/@vuepress/core/lib/node/App.js

Line 118 in 1a930dc

await this.pluginAPI.applyAsyncOption('ready')

So this PR fix this issue

[kefranabg]

Don't you think we should rely on the env variable? see this PR

[meteorlxy]

@kefranabg

I didn't notice that PR.

But I think this PR is not related to the env vars, but the context API isProd, which should be available in ready() hook. They are similar but different 🤔 .

We can rely on env vars, but we still need to set isProd, otherwise we are introducing a breaking change.

[kefranabg]

I mean, instead of using an isProd property, check the NODE_ENV?

[meteorlxy]

Yeah, that's why I said:

We can rely on env vars, but we still need to set isProd, otherwise we are introducing a breaking change.

ctx.isPord is listed in the documentation. So we should be careful if we really want to deperecate it.

[kefranabg]

Hmmm you're right, so maybe we could just do this.isProd = process.NODE_ENV === 'prod' in the createApp function?

[meteorlxy]

close due to #1972