Pass parameter to async request in indexeddb

Question

I have the next code:

$.get('Lubricantes/getListaEquipos', function (data) {
        if (data.length > 0) {
            var peticion = base_datos_local.transaction(['Equipos'], 'readwrite').objectStore('Equipos').clear();

            total_equipos = data.length;

            peticion.onerror = function () {
                console.log('No se pudo limpiar el maestro de equipos.');
            };
            peticion.onsuccess = function (e) {
                for (var i = 0; i < data.length; i++) {
                    var peticion = base_datos_local.transaction(['Equipos'], 'readwrite').objectStore('Equipos').add(data[i]);
                    peticion.onerror = function (e) {
                        console.log('No se pudo cargar el equipo' + i);
                    };
                    peticion.onsuccess = function (e) {
                        console.log('Equipo ' + i + ' agregado');
                    };
                }
            };                                
        }
    });

When this execute the var i don't exist, how can pass to add method the value of i?

possible duplicate of [Javascript closure inside loops - simple practical example](http://stackoverflow.com/questions/750486/javascript-closure-inside-loops-simple-practical-example) — Benjamin Gruenbaum, Apr 23 '14 at 16:32

buley · Answer 1 · 2014-04-23T18:57:50.987

Async is fun, isn't it?

I'll save you the lecture on scopes and variable references and just recommend that you just wrap the guts of your for loop into an "immediately invoked anonymous function" like so:

    $.get('Lubricantes/getListaEquipos', function (data) {
        if (data.length > 0) {
            var peticion = base_datos_local.transaction(['Equipos'], 'readwrite').objectStore('Equipos').clear();

            total_equipos = data.length;

            peticion.onerror = function () {
                console.log('No se pudo limpiar el maestro de equipos.');
            };
            peticion.onsuccess = function (e) {
                for (var i = 0; i < data.length; i++) {
                    (function(entrada, j) {
                        var peticion = base_datos_local.transaction(['Equipos'], 'readwrite').objectStore('Equipos').add(entrada);
                        peticion.onerror = function (e) {
                            console.log('No se pudo cargar el equipo' + j);
                        };
                        peticion.onsuccess = function (e) {
                            console.log('Equipo ' + j + ' agregado');
                        };
                    })(data[i], i);
                }
            };                                
        }
    });

data[i] is evaluated immediately and passed in as an argument to this closure, so you'll have the correct reference in scope when the callbacks eventually fire.

Taylor, the parameter needs to be passed to the function also, I've made edit to your answer — Deni Spasovski, Apr 23 '14 at 18:52

Pass parameter to async request in indexeddb

1 Answers1