Question

I asked this question earlier this morning
“here is my JSON file :

[
{
    "Week": "1145",
    "Sev_Logged": "3_major",
    "From": "IN1"
},
{
    "Week": "1145",
    "Sev_Logged": "4_minor",
    "From": "IN1"
},
{
    "Week": "1145",
    "Sev_Logged": "4_minor",
    "From": "IN1"
},
{
    "Week": "1145",
    "Sev_Logged": "4_minor",
    "From": "IN1"
},
{
    "Week": "1145",
    "Sev_Logged": "4_minor",
    "From": "IN1"
},
{
    "Week": "1145",
    "Sev_Logged": "4_minor",
    "From": "IN2"
},
{
    "Week": "1145",
    "Sev_Logged": "3_major",
    "From": "IN2"
},
];

I want to count the “from : IN1” field for each “week”, per example for week : 1145 i’d get : 3, and for “From : IN2” i’d get 2

Thanks”

Thank you VDP for your answer, so I did this :
My store is now like :

Ext.define('Metrics.store.GraphData', {
extend : 'Ext.data.Store',
model : 'Metrics.model.GraphData',
autoload : true,

proxy : {
    type : 'ajax',
    url : 'data/metrics_data.json',
    reader : {
        type : 'json',
        root : 'data',
        successProperty : 'success'
    }
},
//data : GraphData, //povide inline data or load using proxy
countBy: function(param){
    var count = {};
    this.each(function(item){
        var type = item.get(param);
        if (Ext.isDefined(count[type])){
            count[type]++;
        } else {
            count[type] = 1;
        }                               
    });
    return count;
}
});

And my model :

Ext.define('Metrics.model.GraphData', {
extend: 'Ext.data.Model',
//fields: ['week', 'sev']
fields : [ 
    {name: 'Week',  type: 'int'},
    {name: 'Sev_Logged',   type: 'string'},
    {name: 'From', type: 'string'}
]
});

Since i’m using extjs 4 with MVC model, I have made a controller wich controls the event of a button, right now it looks like this :

launchGraph : function(button){
console.log('clicked the apply button');
var chartStore = this.getGraphDataStore();
chartStore.load({
    callback: this.onGraphDataLoad,
    scope: this,
    console.log(chartStore.countBy("From"))
    });

But when I click the apply button I get this error in my controller :

"Uncaught SyntaxError: Unexpected token . "

And it points to the line :

 "console.log(chartStore.countBy("From"))"

It seems like i have an error in the referencing to my store. Any ideas?

Answer 1

If you are using the array you provide you can just use the mimikomi’s answer or a similar ExtJS version of it:

here is a fiddle

function countBy(data, param) {
    var count = {};
    Ext.each(data, function(item){
        var type = item[param];
        if (Ext.isDefined(count[type]))  {
            count[type]++;
        } else {
            count[type] = 1;
        }  
    });
    return count;
}

If you load that json from an external location it’s best practice to load it in a store. You define a model, a store and add ‘special’ functions to your store for example.

Ext.define('Week', {
    extend: 'Ext.data.Model',
    fields: [
        {name: 'Week',  type: 'int'},
        {name: 'Sev_Logged',   type: 'string'},
        {name: 'From', type: 'string'}
    ]
});

var store = Ext.create('Ext.data.Store', {
    model: 'Week',
    data : data, //povide inline data or load using proxy
    countBy: function(param){
        var count = {};
        this.each(function(item){
            var type = item.get(param);
            if (Ext.isDefined(count[type])){
                count[type]++;
            } else {
                count[type] = 1;
            }                               
        });
        return count;
    }
});

var countObject = store.countBy("From");

alert(Ext.encode(countObject));
//chrome developper tools, safari, opera can show us the contents of objects in a log too. IE, FF however only tell us it is an object. (pretty useless)
console.log(countObject);
//you can chose you're favorite notation to retreve the value (but I hope you knew this, it's pretty basic javascript)
console.log(countObject.IN1); 
console.log(countObject['IN2']);

Here is a fiddle.

More info on loading json dynamically into a store via ajax (using a proxy)