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javascriptnode.jsknex.js

Loop value can not work inside knex in node js

I tried to get loop values inside knex function but I got final value of a loop.

for (i = 0; i < 10; i++) {

    knex_in.raw(query).then(function (result) {
                    console.log(i)
    });

    }

Need help.

Solution

  • The counter in your loop (i) is a global variable. On each iteration of your loop, you are creating a promise. By the time your promises have resolved, the loop is complete, therefore i is the final value.

    The solution is to save the value of i in a scoped variable. This can be done in a few ways, here are two:

    You can use let (depending on ES6 support)

    for (let i = 0; i < 10; i++) {

  setTimeout(function() {
    console.log(i);
  }, 500);

}

    Or you could store the value of i in a scoped variable by creating a function:

    function someFunction(value) {
  setTimeout(function() {
    console.log(value);
  }, 500);
}

for (i = 0; i < 10; i++) {
  someFunction(i)
}