Following is my sqlhelper.js

var req = require("request");
var tp = require('tedious-promises');
var dbConfig = require('../config/connectionString.json');
var TYPES = require('tedious').TYPES;

function SQLHelper() {
}

SQLHelper.prototype.ExecuteDataset = function(query, params, callback, failure) {

    tp.setConnectionConfig(dbConfig);
    tp.sql(q);
    $(params).each(function(idx) {
        var p = params[idx];
        tp.parameter(p.name, p.value);
    });

    tp.execute()
        .then(function(results) {
            callback(results)
        }).fail(function(err) {
            failure(err);
        });
};

module.exports = SQLHelper;

I have used it like this

var sqlHelper = require('../SQLHelper.js');
sqlHelper.ExecuteDataset(q, params, function(results) {//Here I get error
                console.log(results)
            },
            function(err) {
                console.log(err);
            });

I get following error TypeError: sqlHelper.ExecuteDataset is not a function

I dont know whats wrong here. Kindly help.

Following is my sqlhelper.js

var req = require("request");
var tp = require('tedious-promises');
var dbConfig = require('../config/connectionString.json');
var TYPES = require('tedious').TYPES;

function SQLHelper() {
}

SQLHelper.prototype.ExecuteDataset = function(query, params, callback, failure) {

    tp.setConnectionConfig(dbConfig);
    tp.sql(q);
    $(params).each(function(idx) {
        var p = params[idx];
        tp.parameter(p.name, p.value);
    });

    tp.execute()
        .then(function(results) {
            callback(results)
        }).fail(function(err) {
            failure(err);
        });
};

module.exports = SQLHelper;

I have used it like this

var sqlHelper = require('../SQLHelper.js');
sqlHelper.ExecuteDataset(q, params, function(results) {//Here I get error
                console.log(results)
            },
            function(err) {
                console.log(err);
            });

I get following error TypeError: sqlHelper.ExecuteDataset is not a function

I dont know whats wrong here. Kindly help.

• javascript
• node.js

1 Answer 1

You have to create an instance of SQLHelper before it will have the prototype methods. Prototype properties are available on an instance of the object, not on the constructor.

If you want a singleton (only one object that every one shares), you can do this:

// export an instance of our object
module.exports = new SQLHelper();

Or, if you want a separate object each time you use it, you can change where you use it to this:

// load module and create an instance
let sqlHelper = new (require('../SQLHelper.js'))();

Or, if you don't actually have any instance data and you just want to use a namespace, you can do this:

let SQLHelper = {};
SQLHelper.ExecuteDataset  = ...

module.exports = SQLHelper;