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next.js/lib/utils.js
Naoyuki Kanezawa 0b3db91731 Fix handling finished response (#889)
* allows to not return props if response is already finished on getInitialProps

* check res.finished after getInitialProps call of Document
2017-01-26 16:36:50 +05:30

56 lines
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JavaScript

export function warn (message) {
if (process.env.NODE_ENV !== 'production') {
console.error(message)
}
}
export function execOnce (fn) {
let used = false
return (...args) => {
if (!used) {
used = true
fn.apply(this, args)
}
}
}
export function deprecated (fn, message) {
if (process.env.NODE_ENV === 'production') return fn
let warned = false
const newFn = function (...args) {
if (!warned) {
warned = true
console.error(message)
}
return fn.apply(this, args)
}
// copy all properties
Object.assign(newFn, fn)
return newFn
}
export function printAndExit (message, code = 1) {
if (code === 0) {
console.log(message)
} else {
console.error(message)
}
process.exit(code)
}
export async function loadGetInitialProps (Component, ctx) {
if (!Component.getInitialProps) return {}
const props = await Component.getInitialProps(ctx)
if (!props && (!ctx.res || !ctx.res.finished)) {
const compName = Component.displayName || Component.name
const message = `"${compName}.getInitialProps()" should resolve to an object. But found "${props}" instead.`
throw new Error(message)
}
return props
}