Javascript disadvantages of "single var pattern"

Question

In the JS Design Staps Stefanov book of templates, he writes: “you use one var statement and declare several variables separated by commas”, and then give an example of the “one var” template as follows:

function func() {
    var a = 1,
        b = 2,
        sum = a + b,
        myobject = {},
        i,
        j;

Stefanov additionally writes:

• "It's good practice to also initialize a variable with an initial value at the time of its declaration."
• "You can also do some actual work during the declaration, as is the case with sum = a + b in the previous code."

Now I have the code as follows, declaring the same number of variables with a single var template, but doing a bit more "actual work during declaration":

var html = '{purchaseQty}<br>FR:&nbsp; {fromLoc}'
    ,tpl = new Ext.XTemplate(html)
    ,srcReqLoc = record.get('SRC_REQUEST_LOC').trim()
    ,srcSupLoc = record.get('SRC_SUP_LOC').trim()
    ,fromLoc = srcReqLoc ? srcReqLoc : srcSupLoc
    ,tplCfg = {
        purchaseQty: purchaseQty
        ,fromLoc: fromLoc
    };

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Answer 1

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var html       = '{purchaseQty}<br>FR:&nbsp; {fromLoc}'
    ,tpl       = new Ext.XTemplate(html)

    ,srcReqLoc = record.get('SRC_REQUEST_LOC').trim()
    ,srcSupLoc = record.get('SRC_SUP_LOC').trim()    
    ,fromLoc   = srcReqLoc ? srcReqLoc : srcSupLoc

    ,tplCfg    = {
        purchaseQty: purchaseQty
        ,fromLoc: fromLoc
    };

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Answer 2

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