I'm using Node JS and ExpressJS to write my web server. I use JavaScript OOP fromfew time. I get an error running this class:
class myClass {
constructor(path) {
this.path = path;
}
myFunction(){
var fileControllerInstance = new FileController(this.path);
fileControllerInstance.fileExist(function(fileExist) {
if(fileExist){
console.log("file exist");
this.printLine("test");
}
else
return false;
});
}
printSTR(str){
console.log(str);
}
}
new myClass("filePath").myFunction();
module.exports = myClass;
Running this class I get an error on printSTR function. Error is the follow:
file exist
TypeError: Cannot read properties of undefined (reading 'printSTR')
Without this I get ReferenceError: printSTR is not defined. To solve my problem I need to create another class instance and to use that to call the function. Something like this:
new myClass("filePath").printSTR("test") instead to ``` this.printLine("test"); ```
Why using this my code not working? Thanks
Inside the function(fileExist), this has a different value than outside. To inherit the value inside, you must bind the function:
fileControllerInstance.fileExist(function(fileExist) {
...
}.bind(this));