how to pass parameter to a promise function in javascript?

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To pass parameters to a promise function in javascript, create a parameter function and use promise in a function like the below example.

var getNameById = function (id) {
  return new Promise(function (resolve, reject) {
    // ...
  });
};

getNameById(3).then(function (res) {
  console.log(res);
});

// output: "Stuff worked"

Today, I’m going to show you How do I pass parameters to a promise function in javascript, as above mentioned, I’m going to use the above-mentioned syntax to create and use a promise function with a parameter.

Let’s start today’s tutorial how do you pass parameters to a promise function in javascript?

Javascript promise function with parameter example

Here we will create a parameter function and store it in a variable, in the function we will create a promise with a resolve & reject option where we will check if it is greater than 0 resolve promise or rejects.

var getNameById = function (id) {
  return new Promise(function (resolve, reject) {
    if (id > 0) {
      resolve('Stuff worked!');
    } else {
      reject(Error('It broke'));
    }
  });
};

getNameById(3).then(function (res) {
  console.log(res);
});

// output: "Stuff worked"

ECS 6 promise function with parameter example

Same like javascript we can create a promise function with parameters in ECMAScript 6 also, there is only one difference we don’t need to mention the function keyword for creating a function.

let’s take an example.

const getNameById = (id) => {
  return new Promise((resolve, reject) => {
    if (id > 0) {
      resolve('Stuff worked!');
    } else {
      reject(Error('It broke'));
    }
  });
};

getNameById(3).then(function (res) {
  console.log(res);
});

// output: "Stuff worked"

I hope it helps you, All the best 👍.