# koa-mock-response
> Mock a Rest API or any backend service.
Latest version **1.0.0** (published 2020-02-09) · MIT license · 0 weekly downloads
## Install
```sh
npm install koa-mock-response
pnpm add koa-mock-response
yarn add koa-mock-response
bun add koa-mock-response
```
## Health
**Score 15/100 (F)** — status: abandoned.
Positive: no vulnerabilities.
Warnings: low downloads; no types; no esm support.
Negative: abandoned; low maintenance score.
## Facts
| | |
|---|---|
| Version | 1.0.0 |
| Published | 2020-02-09 |
| First published | 2016-06-21 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | none |
| Module format | CommonJS |
| Node | >=10 |
| Dependencies | 3 |
| Unpacked size | 15.5 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 2 |
| Author | Lloyd Brookes |
| Maintainers | 75lb |
| Keywords | lws, koa, mock |
## Links
- npm: https://www.npmjs.com/package/koa-mock-response
- Repository: https://github.com/lwsjs/koa-mock-response
- Homepage: https://github.com/lwsjs/koa-mock-response#readme
- Issues: https://github.com/lwsjs/koa-mock-response/issues
- npm.io page: https://npm.io/package/koa-mock-response
## Dependencies (3)
- [typical](https://npm.io/package/typical.md) ^6.0.0
- [array-back](https://npm.io/package/array-back.md) ^4.0.1
- [path-to-regexp](https://npm.io/package/path-to-regexp.md) ^6.1.0
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## Recent versions
- 1.0.0 (latest) — 2020-02-09
- 0.2.0 — 2017-07-09
- 0.1.0 — 2017-06-25
- 0.0.2 — 2016-06-22
- 0.0.1 — 2016-06-21
## README
[](https://www.npmjs.org/package/koa-mock-response)
[](https://www.npmjs.org/package/koa-mock-response)
[](https://travis-ci.org/lwsjs/koa-mock-response)
[](https://david-dm.org/lwsjs/koa-mock-response)
[](https://github.com/feross/standard)
# koa-mock-response
Mocks give you full control over the response headers and body returned to the client. They can be used to return anything from a simple html string to a resourceful REST API. Typically, they're used to mock services but can be used for anything.
In the config, define an array called `mocks`. Each mock definition maps a [route](http://expressjs.com/guide/routing.html#route-paths) to a `response`. A simple home page:
```json
{
"mocks": [
{
"route": "/",
"response": {
"body": "Welcome to the Mock Responses example
"
}
}
]
}
```
Under the hood, the property values from the `response` object are written onto the underlying [koa response object](https://github.com/koajs/koa/blob/master/docs/api/response.md). You can set any valid koa response properies, for example [type](https://github.com/koajs/koa/blob/master/docs/api/response.md#responsetype-1):
```json
{
"mocks": [
{
"route": "/",
"response": {
"type": "text/plain",
"body": "Welcome to the Mock Responses example
"
}
}
]
}
```
### Conditional Response
To define a conditional response, set a `request` object on the mock definition. The `request` value acts as a query - the response defined will only be returned if each property of the `request` query matches. For example, return an XML response *only* if the request headers include `accept: application/xml`, else return 404 Not Found.
```json
{
"mocks": [
{
"route": "/two",
"request": { "accepts": "xml" },
"response": {
"body": ""
}
}
]
}
```
### Multiple Potential Responses
To specify multiple potential responses, set an array of mock definitions to the `responses` property. The first response with a matching request query will be sent. In this example, the client will get one of two responses depending on the request method:
```json
{
"mocks": [
{
"route": "/three",
"responses": [
{
"request": { "method": "GET" },
"response": {
"body": "Mock response for 'GET' request on /three
"
}
},
{
"request": { "method": "POST" },
"response": {
"status": 400,
"body": { "message": "That method is not allowed." }
}
}
]
}
]
}
```
### Dynamic Response
The examples above all returned static data. To define a dynamic response, create a mock module. Specify its path in the `module` property:
```json
{
"mocks": [
{
"route": "/four",
"module": "/mocks/stream-self.js"
}
]
}
```
Here's what the `stream-self` module looks like. The module should export a mock definition (an object, or array of objects, each with a `response` and optional `request`). In this example, the module simply streams itself to the response but you could set `body` to *any* [valid value](https://github.com/koajs/koa/blob/master/docs/api/response.md#responsebody-1).
```js
const fs = require('fs')
module.exports = {
response: {
body: fs.createReadStream(__filename)
}
}
```
### Response function
For more power, define the response as a function. It will receive the [koa context](https://github.com/koajs/koa/blob/master/docs/api/context.md) as its first argument. Now you have full programmatic control over the response returned.
```js
module.exports = {
response: function (ctx) {
ctx.body = 'I can do anything i want.
'
}
}
```
If the route contains tokens, their values are passed to the response. For example, with this mock...
```json
{
"mocks": [
{
"route": "/players/:id",
"module": "/mocks/players.js"
}
]
}
```
...the `id` value is passed to the `response` function. For example, a path of `/players/10?name=Lionel` would pass `10` to the response function. Additional, the value `Lionel` would be available on `ctx.query.name`:
```js
module.exports = {
response: function (ctx, id) {
ctx.body = `id: ${id}, name: ${ctx.query.name}
`
}
}
```
### RESTful Resource example
Here's an example of a REST collection (users). We'll create two routes, one for actions on the resource collection, one for individual resource actions.
```json
{
"mocks": [
{ "route": "/users", "module": "/mocks/users.js" },
{ "route": "/users/:id", "module": "/mocks/user.js" }
]
}
```
Define a module (`users.json`) defining seed data:
```json
[
{ "id": 1, "name": "Lloyd", "age": 40, "nationality": "English" },
{ "id": 2, "name": "Mona", "age": 34, "nationality": "Palestinian" },
{ "id": 3, "name": "Francesco", "age": 24, "nationality": "Italian" }
]
```
The collection module:
```js
const users = require('./users.json')
/* responses for /users */
const mockResponses = [
/* Respond with 400 Bad Request for PUT and DELETE - inappropriate on a collection */
{ request: { method: 'PUT' }, response: { status: 400 } },
{ request: { method: 'DELETE' }, response: { status: 400 } },
{
/* for GET requests return a subset of data, optionally filtered on 'minAge' and 'nationality' */
request: { method: 'GET' },
response: function (ctx) {
ctx.body = users.filter(user => {
const meetsMinAge = (user.age || 1000) >= (Number(ctx.query.minAge) || 0)
const requiredNationality = user.nationality === (ctx.query.nationality || user.nationality)
return meetsMinAge && requiredNationality
})
}
},
{
/* for POST requests, create a new user and return the path to the new resource */
request: { method: 'POST' },
response: function (ctx) {
const newUser = ctx.request.body
users.push(newUser)
newUser.id = users.length
ctx.status = 201
ctx.response.set('Location', `/users/${newUser.id}`)
}
}
]
module.exports = mockResponses
```
The individual resource module:
```js
const users = require('./users.json')
/* responses for /users/:id */
const mockResponses = [
/* don't support POST here */
{ request: { method: 'POST' }, response: { status: 400 } },
/* for GET requests, return a particular user */
{
request: { method: 'GET' },
response: function (ctx, id) {
ctx.body = users.find(user => user.id === Number(id))
}
},
/* for PUT requests, update the record */
{
request: { method: 'PUT' },
response: function (ctx, id) {
const updatedUser = ctx.request.body
const existingUserIndex = users.findIndex(user => user.id === Number(id))
users.splice(existingUserIndex, 1, updatedUser)
ctx.status = 200
}
},
/* DELETE request: remove the record */
{
request: { method: 'DELETE' },
response: function (ctx, id) {
const existingUserIndex = users.findIndex(user => user.id === Number(id))
users.splice(existingUserIndex, 1)
ctx.status = 200
}
}
]
module.exports = mockResponses
```
* * *
© 2017-20 Lloyd Brookes <75pound@gmail.com>.
---
_Source: https://npm.io/package/koa-mock-response · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._