在 java 脚本中调用 function 一次并关闭

Question

I want call function once in java script and for implement this idea I write this code and I use closure

function initialize() {
  let called = 0;
  return function() {
    if (called > 0) {
      return
    } else {
      called++;
      console.log('view has been set!')
    }

  }
}

const start1 = initialize();
start1();
start1();
start1();

I call start1 function third time and when I run this code I get once this output "view has been set." in console. But I notice I can call initialize function many times and create different start function for example

const start1 = initialize();
const start2 = initialize();
start1();
start2();

This time in output I have twice "view has been set.". How can I fix that. thanks.

Answer 1

By keeping the structure of calling initialize , you need a closure which works without the first call of initialize .

Then you need a nested function to get the inner function for the working part.

 const initialize = (() => { let called = 0; return () => () => { if (called <= 0) { called++; console.log('view has been set;'); } }; })(); const start1 = initialize(); const start2 = initialize(); start1(); start2();

Answer 2

When you call initialize function every times a new called variable is created which assigned to value 0 .

Answer 3

I believe what you are looking for is a singleton. You can try this approach.

 class initialize { constructor(){ if(. initialize.instance){ this;_data = []. initialize;instance = this. console.log('view has been set;') } return initialize.instance; } dosmt=()=>{ console.log("smt" ) } } const instance = new initialize(); Object;freeze(instance); const start1 = new initialize(); const start2 = new initialize(). const start3 = new initialize(). start1.dosmt() start2.dosmt() start3.dosmt()