4dkankan-components/packages/hooks/use-global-config/index.ts

import { computed, getCurrentInstance, inject, provide, ref, unref } from 'vue'
import { configProviderContextKey } from '@kankan-components/tokens'
import { debugWarn, keysOf } from '@kankan-components/utils'

import type { MaybeRef } from '@vueuse/core'
import type { App, Ref } from 'vue'
import type { ConfigProviderContext } from '@kankan-components/tokens'

// this is meant to fix global methods like `ElMessage(opts)`, this way we can inject current locale
// into the component as default injection value.
// refer to: https://github.com/element-plus/element-plus/issues/2610#issuecomment-887965266
const globalConfig = ref<ConfigProviderContext>()

export function useGlobalConfig<K extends keyof ConfigProviderContext, D extends ConfigProviderContext[K]>(key: K, defaultValue?: D): Ref<Exclude<ConfigProviderContext[K], undefined> | D>
export function useGlobalConfig(): Ref<ConfigProviderContext>
export function useGlobalConfig(key?: keyof ConfigProviderContext, defaultValue = undefined) {
    const config = getCurrentInstance() ? inject(configProviderContextKey, globalConfig) : globalConfig
    if (key) {
        return computed(() => config.value?.[key] ?? defaultValue)
    } else {
        return config
    }
}

export const provideGlobalConfig = (config: MaybeRef<ConfigProviderContext>, app?: App, global = false) => {
    const inSetup = !!getCurrentInstance()
    const oldConfig = inSetup ? useGlobalConfig() : undefined

    const provideFn = app?.provide ?? (inSetup ? provide : undefined)
    if (!provideFn) {
        debugWarn('provideGlobalConfig', 'provideGlobalConfig() can only be used inside setup().')
        return
    }

    const context = computed(() => {
        const cfg = unref(config)
        if (!oldConfig?.value) return cfg
        return mergeConfig(oldConfig.value, cfg)
    })
    provideFn(configProviderContextKey, context)
    if (global || !globalConfig.value) {
        globalConfig.value = context.value
    }
    return context
}

const mergeConfig = (a: ConfigProviderContext, b: ConfigProviderContext): ConfigProviderContext => {
    const keys = [...new Set([...keysOf(a), ...keysOf(b)])]
    const obj: Record<string, any> = {}
    for (const key of keys) {
        obj[key] = b[key] ?? a[key]
    }
    return obj
}