(JavaScript) JSON Paths

Demonstrates using "Chilkat JSON Paths" to access parts of a JSON document, or to iterate over parts.

This example uses the following JSON document:

{
    "nestedArray" : [
			[
				[1,2,3],
				[4,5,6],
				[7,8,9,10]
			],
			[
				[11,12,13],
				[14,15,16],
				[17,18,19,20]
			],
			[
				[21,22,23],
				[24,25,26],
				[27,28,29,30],
				[31,32,33,34,35,36]
			]
		],

	"nestedObject" : {
		"aaa" : {
			"bb1" : {
				"cc1" : "c1Value",
				"cc2" : "c2Value",
				"cc3" : "c3Value"
			},
			"bb2" : {
				"dd1" : "d1Value",
				"dd2" : "d2Value",
				"dd3" : "d3Value"
			}
		}
	},

	"mixture" : {
		"arrayA" : [  
			{ "fruit": "apple", "animal": "horse", "job": "fireman", "colors": ["red","blue","green"] },
			{ "fruit": "pear", "animal": "plankton", "job": "waiter", "colors": ["yellow","orange","purple"] },
			{ "fruit": "kiwi", "animal": "echidna", "job": "astronaut", "colors": ["magenta","tan","pink"] }
			]
	},


        "name.with.dots" : { "grain" : "oats" }

	
}

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

var success = false;

var json = new CkJsonObject();
json.EmitCompact = false;

// Assume the file contains the data as shown above..
success = json.LoadFile("qa_data/json/pathSample.json");
if (success == false) {
    console.log(json.LastErrorText);
    return;
}

// First, let's get the value of "cc1"
// The path to this value is: nestedObject.aaa.bb1.cc1
console.log(json.StringOf("nestedObject.aaa.bb1.cc1"));

// Now let's get number 18 from the nestedArray.
// It is located at nestedArray[1][2][1]
// (remember: Indexing is 0-based)
console.log("This should be 18: " + json.IntOf("nestedArray[1][2][1]"));

// We can do the same thing in a more roundabout way using the 
// I, J, and K properties.  (The I,J,K properties will be convenient
// for iterating over arrays, as we'll see later.)
json.I = 1;
json.J = 2;
json.K = 1;
console.log("This should be 18: " + json.IntOf("nestedArray[i][j][k]"));

// Let's iterate over the array containing the numbers 17, 18, 19, 20.
// First, use the SizeOfArray method to get the array size:
var sz = json.SizeOfArray("nestedArray[1][2]");
// The size should be 4.
console.log("size of array = " + sz + " (should equal 4)");

// Now iterate...
var i;
for (i = 0; i <= sz - 1; i++) {
    json.I = i;
    console.log(json.IntOf("nestedArray[1][2][i]"));
}

// Let's use a triple-nested loop to iterate over the nestedArray:
var j;
var k;

// szI should equal 1.
var szI = json.SizeOfArray("nestedArray");
for (i = 0; i <= szI - 1; i++) {
    json.I = i;

    var szJ = json.SizeOfArray("nestedArray[i]");
    for (j = 0; j <= szJ - 1; j++) {
        json.J = j;

        var szK = json.SizeOfArray("nestedArray[i][j]");
        for (k = 0; k <= szK - 1; k++) {
            json.K = k;

            console.log(json.IntOf("nestedArray[i][j][k]"));
        }

    }

}

// Now let's examine how to navigate to JSON objects contained within JSON arrays.
// This line of code gets the value "kiwi" contained within "mixture"
console.log(json.StringOf("mixture.arrayA[2].fruit"));

// This line of code gets the color "yellow"
console.log(json.StringOf("mixture.arrayA[1].colors[0]"));

// Getting an object at a path:
// This gets the 2nd object in "arrayA"

var obj2 = new CkJsonObject();
json.ObjectOf2("mixture.arrayA[1]",obj2);

// This object's "animal" should be "plankton"
console.log(obj2.StringOf("animal"));

// Note that paths are relative to the object, not the absolute root of the JSON document.
// Starting from obj2, "purple" is at "colors[2]"
console.log(obj2.StringOf("colors[2]"));

// Getting an array at a path:
// This gets the array containing the colors red, green, blue:

var arr1 = new CkJsonArray();
json.ArrayOf2("mixture.arrayA[0].colors",arr1);

var szArr1 = arr1.Size;
for (i = 0; i <= szArr1 - 1; i++) {
    console.log(i + ": " + arr1.StringAt(i));
}

// The Chilkat JSON path uses ".", "[", and "]" chars for separators.  When a name
// contains one of these chars, use double-quotes in the path:
console.log(json.StringOf("\"name.with.dots\".grain"));