| Yang Guo | 4fd355c | 2019-09-19 08:59:03 | [diff] [blame] | 1 | # wrappy |
| 2 | |
| 3 | Callback wrapping utility |
| 4 | |
| 5 | ## USAGE |
| 6 | |
| 7 | ```javascript |
| 8 | var wrappy = require("wrappy") |
| 9 | |
| 10 | // var wrapper = wrappy(wrapperFunction) |
| 11 | |
| 12 | // make sure a cb is called only once |
| 13 | // See also: http://npm.im/once for this specific use case |
| 14 | var once = wrappy(function (cb) { |
| 15 | var called = false |
| 16 | return function () { |
| 17 | if (called) return |
| 18 | called = true |
| 19 | return cb.apply(this, arguments) |
| 20 | } |
| 21 | }) |
| 22 | |
| 23 | function printBoo () { |
| 24 | console.log('boo') |
| 25 | } |
| 26 | // has some rando property |
| 27 | printBoo.iAmBooPrinter = true |
| 28 | |
| 29 | var onlyPrintOnce = once(printBoo) |
| 30 | |
| 31 | onlyPrintOnce() // prints 'boo' |
| 32 | onlyPrintOnce() // does nothing |
| 33 | |
| 34 | // random property is retained! |
| 35 | assert.equal(onlyPrintOnce.iAmBooPrinter, true) |
| 36 | ``` |
