node-promisify
Convert a callback-based api to one that returns a promise.
NOTE:
- Own properties are preserved. But other inherited properties such as
name
,length
,toString
, do not preserve. - Custom promise can be used instead of the native. But no polyfill is applied when your node version does not support promise.
- Multiple values can be resolved when the
argc
option is specified.
Example
var promisify = { process} async { return a + b} var promisified = console 1 2 3 4 1 2 3 4
output:
⌘ node example/sums.js
Sync sum: 3
Async sum: 3
Two sums: [ 3, 6 ]
All sums: [ 3, 6, 10 ]
pfn = promisify(fn, opts)
Return a new function which returns a promise.
Sugar: pfn = promisify(fn, argc)
, pfn = promisify(fn, promise)
fn
The async function to be promisified.
Type: Function
Signature: fn(arg1, arg2, ..., done)
opts
promise
Specify a custom promise constructor.
Type: Function
argc
Specify the number of values to be resolved.
Type: Number
Default: null
When specified, the returned promise always resolve to an array.
If not specified, only the first value is resolved.
To resolve all possible values, specify a negative argc
.