egg-plugin-context/app/middleware/withContext.js

An egg middleware for adding contexts

const { getType, setProperty } = require('js-cool')

module.exports = (options = {}, config = {}) => {
	return async function withContext(ctx, next) {
		const { contextName = 'context' } = config
		if (getType(options) === 'function') options = (await options(ctx)) || {}
		if (getType(options) !== 'object')
			throw new Error('options must be an object, or a function, and return an object')
		ctx[contextName] = ctx[contextName] || {}
		for (const key in options) {
			let value = options[key]
			if (getType(options[key]) === 'function') value = (await options[key](ctx)) || null
			// write to ctx[contextName]
			setProperty(ctx[contextName], key, value)
		}

		return await next()
	}
}