CODEWITHSUNDEEP
javascriptjsonnode.js
user561810
user561810

Reputation: 11

How to get the value of variable a from below code?

request(target, function (err, resp, body) {
    $ = cheerio.load(body);
    links = $('a'); 
    $(links).each(function (i, link) {
        if ($(link).text().match('worker')) {
            var a = $(link).attr('href').toString();
        }
    });
});

I want to use the output of variable a in further program. Any pointers?

Upvotes: 0

Views: 103

Answers (3)

Arg0n
Arg0n

Reputation: 8423

If you do like this:

JavaScript

var savedLinks;
request(target, function (err, resp, body) {
    savedLinks = [];
    $ = cheerio.load(body);
    links = $('a'); 
    $(links).each(function (i, link) {
        if ($(link).text().match('worker')) {
            var a = $(link).attr('href').toString();
            savedLinks.push(a);
        }
    });
});

Then you can iterate through savedLinks.

Like this:

for(var i = 0; i < savedLinks.length; i++) {
   console.log(savedLinks[i]);
}

You have to call the function request at some point for it to be initialized though of course.

Upvotes: 0

Alessio Cantarella
Alessio Cantarella

Reputation: 5201

You have two alternative ways to give the variable a a global scope:

  1. Declare it outside the request function (*) and just assign it inside the each cycle (**), i.e.:

    var a; // (*)
request(target, function (err, resp, body) {
    $ = cheerio.load(body);
    links = $('a'); 
    $(links).each(function (i, link) {
        if ($(link).text().match('worker')) {
            a = $(link).attr('href').toString(); // (**)
        }
    });
});

  2. Simply remove the variable declaration inside the each cycle (*), i.e.:

    request(target, function (err, resp, body) {
    $ = cheerio.load(body);
    links = $('a'); 
    $(links).each(function (i, link) {
        if ($(link).text().match('worker')) {
            a = $(link).attr('href').toString(); // (*)
        }
    });
});

    (If you assign a value to a variable that has not been declared, it will automatically become a global variable).

Upvotes: 2

CherryNerd
CherryNerd

Reputation: 1314

the var declaration is function-scoped. This means it can only be used within the function it's declared in.

Explanation:

// 'a' does not exist
$(links).each(function (i, link) {
    if($(link).text().match('worker')){
        var a=$(link).attr('href').toString();
        // 'a' exists'
    }
    // 'a' exists'
});
// 'a' does not exist

There are certain 'hacks' out there, like not 'declaring' it with var, let or const. Doing it like that automatically makes it 'global', but this ofcourse has it drawbacks regarding memory usage and potential memory leaks (the same can be achieved with putting var outside of the functions).

A better way to use it might be to split the functionality up a bit more and just let one function call another (or with callbacks, but I hate callbacks and they're not the solution to everything).

Upvotes: 0

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