onetime
Ensure a function is only called once
When called multiple times it will return the return value from the first call.
Unlike the module once, this one isn't naughty and extending Function.prototype.
Install
npm install onetimeUsage
import onetime from 'onetime';
let index = 0;
const foo = onetime(() => ++index);
foo(); //=> 1
foo(); //=> 1
foo(); //=> 1
onetime.callCount(foo); //=> 3import onetime from 'onetime';
const foo = onetime(() => {}, {throw: true});
foo();
foo();
//=> Error: Function `foo` can only be called onceAPI
onetime(fn, options?)
Returns a function that only calls fn once.
fn
Type: Function
The function that should only be called once.
options
Type: object
throw
Type: boolean
Default: false
Throw an error when called more than once.
onetime.callCount(fn)
Returns a number representing how many times fn has been called.
Note: It throws an error if you pass in a function that is not wrapped by onetime.
import onetime from 'onetime';
const foo = onetime(() => {});
foo();
foo();
foo();
console.log(onetime.callCount(foo));
//=> 3fn
Type: Function
The function to get call count from.
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