A Headers class polyfill and transformation library.
npm install headers-utils

headers-utilsA Headers class polyfill and transformation library.
Various request issuing libraries utilize a different format of headers. This library chooses the Headers instance as the middle-ground between server and client, and provides functions to convert that instance to primitives and vice-versa.
``bash`
$ npm install headers-utils
This package exports the Headers class that polyfills the native window.Headers implementation. This allows you to construct and manage headers using the same API in non-browser environments.
`js
import { Headers } from 'headers-utils'
const headers = new Headers({
Accept: '/',
'Content-Type': 'application/json',
})
headers.get('accept') // "/"
`
The Headers polyfill instance supports the same methods as the standard Headers instance:
- .has()
- .get()
- .set()
- .append()
- .delete()
- .forEach()
As well as the iterator methods:
- .keys()
- .values()
- .entries()
In addition, the polyfill instance has the following methods:
- .all()
Returns the object of the _normalized_ header name/value pairs.
`js
const headers = new Headers({
Accept: '/',
'Content-Type': 'application/json',
})
headers.all()
// { "accept": "/", "content-type": "application/json" }
`
- .raw()
Similar to the .all() method, .raw() returns an object consisting of the header name/value pairs, but preserving raw header names.
`js
const headers = new Headers({
Accept: '/',
'Content-Type': 'application/json',
})
headers.raw()
// { "Accept": "/", "Content-Type": "application/json" }
`
- headersToString: (h: Headers): string
`js
import { headersToString } from 'headers-utils'
headersToString(
new Headers({
connection: 'keep-alive',
'content-type': ['text/plain', 'image/png'],
})
)
// connetion: keep-alive
// content-type: text/plain, image/png
`
- headersToList: (h: Headers): Array<[string, string | string[]]>
`js
import { headersToList } from 'headers-utils'
headersToList(
new Headers({
connection: 'keep-alive',
'content-type': ['text/plain', 'image/png'],
})
)
// [['connection', 'keep-alive'], ['content-type', ['text/plain', 'image/png']]]
`
- headersToObject: (h: Headers): Record
`js
import { headersToObject } from 'headers-utils'
headersToObject(
new Headers({
connection: 'keep-alive',
'content-type': ['text/plain', 'image/png'],
})
)
// { connection: 'keep-alive', 'content-type': ['text/plain', 'image/png'] }
`
- stringToHeaders: (s: string): Headers
`js
import { stringToHeaders } from 'headers-utils'
const stringToHeaders(
connection: keep-alive
content-type: text/plain, image/png)`
// Headers { connection: 'keep-alive', 'content-type': ['text/plain', 'image/png'] }
- listToHeaders: (l: Array<[string, string | string[]]>): Headers
`js
import { listToHeaders } from 'headers-utils'
listToHeaders([
['connection', 'keep-alive'],
['content-type', ['text/plain', 'image/png']],
])
// Headers { connection: 'keep-alive', 'content-type': ['text/plain', 'image/png'] }
`
- objectToHeaders: (o: Record
`js
import { objectToHeaders } from 'headers-utils'
objectToHeaders({
connection: 'keep-alive',
'content-type': ['text/plain', 'image/png'],
})
// Headers { connection: 'keep-alive', 'content-type': ['text/plain', 'image/png'] }
`
---
- reduceHeadersObject:
`js
import { reduceHeadersObject } from 'headers-utils'
reduceHeadersObject <
HeadersObject >
({
Accept: '/',
'Content-Type': ['application/json', 'text/plain'],
},
(headers, name, value) => {
headers[name.toLowerCase()] = value
return headers
},
{})
// { 'accept': '/', 'content-type': ['application/json', 'text/plain'] }
`
- appendHeader: (o: Record
`js
import { appendHeader } from 'headers-utils'
appendHeader(
{ 'content-type': 'application/json' },
'content-type',
'text/plain'
)
// { 'content-type': ['application/json', 'text/plain']}
`
- flattenHeadersList: (l: Array<[string, string | string[]]>): Array
`js
import { flattenHeadersList } from 'headers-utils'
flattenHeadersList([['content-type', ['text/plain', 'image/png']]])
// ['content-type', 'text/plain; image/png']
`
- flattenHeadersObject: (o: Record
`js
import { flattenHeadersObject } from 'headers-utils'
flattenHeadersObject({
'content-type': ['text/plain', 'image/png'],
})
// { 'content-type': 'text/plain; image/png' }
``