如何在 JavaScript 中打印 object 数组？

Question

I have created an object array in JavaScript. How can I print the object array in the browser window, similar to print_r function in PHP?

var lineChartData = [{
            date: new Date(2009, 10, 2),
            value: 5
        }, {
            date: new Date(2009, 10, 25),
            value: 30
        }, {
            date: new Date(2009, 10, 26),
            value: 72,
            customBullet: "images/redstar.png"
        }];

Answer 1

Simply stringify your object and assign it to the innerHTML of an element of your choice.

yourContainer.innerHTML = JSON.stringify(lineChartData);

If you want something prettier, do

yourContainer.innerHTML = JSON.stringify(lineChartData, null, 4);

 var lineChartData = [{ date: new Date(2009, 10, 2), value: 5 }, { date: new Date(2009, 10, 25), value: 30 }, { date: new Date(2009, 10, 26), value: 72, customBullet: "images/redstar.png" }]; document.getElementById("whereToPrint").innerHTML = JSON.stringify(lineChartData, null, 4);

 <pre id="whereToPrint"></pre>

But if you just do this in order to debug, then you'd better use the console with console.log(lineChartData) .

Answer 2

Did you check

console.table(yourArray);

More infos here: https://developer.mozilla.org/en-US/docs/Web/API/Console/table

Answer 3

如果您使用的是 Chrome，您还可以使用

console.log( yourArray );

Answer 4

There is a wonderful print_r implementation for JavaScript in php.js library.

Note, you should also add echo support in the code.

DEMO: http://jsbin.com/esexiw/1

Answer 5

Simple function to alert contents of an object or an array .
Call this function with an array or string or an object it alerts the contents.

function print_r(printthis, returnoutput) {
    var output = '';

    if($.isArray(printthis) || typeof(printthis) == 'object') {
        for(var i in printthis) {
            output += i + ' : ' + print_r(printthis[i], true) + '\n';
        }
    }else {
        output += printthis;
    }
    if(returnoutput && returnoutput == true) {
        return output;
    }else {
        alert(output);
    }
}

var data = [1, 2, 3, 4];
print_r(data);

Answer 6

document.getElementById('container').innerHTML = lineChartData[array_index]

Answer 7

I use the below function to display a readout in firefox console log:

////        make printable string for console readout, recursively
var make_printable_object = function(ar_use)
{
////        internal arguments
var in_tab = arguments[1];
var st_return = arguments[2];
////        default vales when applicable
if (!in_tab) in_tab = 0;
if (!st_return) st_return = "";
////        add depth
var st_tab = "";
for (var i=0; i < in_tab; i++) st_tab = st_tab+"-~-~-";

////        traverse given depth and build string
for (var key in ar_use)
{
    ////        gather return type
    var st_returnType = typeof ar_use[key];
    ////        get current depth display
    var st_returnPrime = st_tab+ "["+key+"] ->"+ar_use[key]+"< is {"+st_returnType+"}";
    ////        remove linefeeds to avoid printout confusion
    st_returnPrime = st_returnPrime.replace(/(\r\n|\n|\r)/gm,"");
    ////        add line feed
    st_return = st_return+st_returnPrime+"\n";
    ////         stop at a depth of 15
    if (in_tab>15) return st_return;
    ////        if current value is an object call this function
    if ( (typeof ar_use[key] == "object") & (ar_use[key] != "null") & (ar_use[key] != null) ) st_return = make_printable_object(ar_use[key], in_tab+1, st_return);


}

////        return complete output
return st_return;

};

Example:

console.log( make_printable_object( some_object ) );

Alternatively , you can just replace:

st_return = st_return+st_returnPrime+"\n";

with

st_return = st_return+st_returnPrime+"<br/>";

to print out in a html page.

Answer 8

You can just use the following syntax and the object will be fully shown in the console:

console.log('object evt: %O', object);

I use Chrome browser don't know if this is adaptable for other browsers.

Answer 9

Emm... Why not to use something like this?

 function displayArrayObjects(arrayObjects) { var len = arrayObjects.length, text = ""; for (var i = 0; i < len; i++) { var myObject = arrayObjects[i]; for (var x in myObject) { text += ( x + ": " + myObject[x] + " "); } text += "<br/>"; } document.getElementById("message").innerHTML = text; } var lineChartData = [{ date: new Date(2009, 10, 2), value: 5 }, { date: new Date(2009, 10, 25), value: 30 }, { date: new Date(2009, 10, 26), value: 72, customBullet: "images/redstar.png" }]; displayArrayObjects(lineChartData);

 <h4 id="message"></h4>

result:

date: Mon Nov 02 2009 00:00:00 GMT+0200 (FLE Standard Time) value: 5 
date: Wed Nov 25 2009 00:00:00 GMT+0200 (FLE Standard Time) value: 30 
date: Thu Nov 26 2009 00:00:00 GMT+0200 (FLE Standard Time) value: 72 customBullet: images/redstar.png 

jsfiddle

Answer 10

you can use console.log() to print object

console.log(my_object_array);

in case you have big object and want to print some of its values then you can use this custom function to print array in console

this.print = function (data,bpoint=0) {
    var c = 0;
    for(var k=0; k<data.length; k++){
        c++;
        console.log(c+'  '+data[k]);
        if(k!=0 && bpoint === k)break;  
    }
}

usage

print(array);   // to print entire obj array

or

print(array,50);  // 50 value to print only 

Answer 11

The question is: How to print object array in JavaScript? To print one use this.

document.write(array[i])

Will print one item where i is the array count starting at 0.

document.write(array)

Will print all of them.

Answer 12

While this doesn't answer the question specifically in terms of a JS function similar to print_r , it doesn't require a lot of setup to get it working and displaying data in an easy-on-the-eyes format.

The inspiration for this solution

 const result = document.getElementById('result'); const lineChartData = [ { date: "2009-10-2", value: 5 }, { date: "2009-10-25", value: 30 }, { date: "2009-10-26", value: 72 } ]; function funCall() { let html = `<table border='1|1' cellpadding='2' cellspacing='0'> <tr> <th>Date</th> <th>Value</th> </tr>`; setTimeout(() => { for (let i = 0; i < lineChartData.length; i++) { html += `<tr> <td>${lineChartData[i].date}</td> <td>${lineChartData[i].value}</td> </tr>`; } result.innerHTML = html; }, 500); } funCall();

 * { box-sizing: border-box; font-family: sans-serif; font-size: 0.9rem; } table { width: 150px; margin: 0 auto; } th { background: #654789; color: #fff; } tr:nth-of-type(odd) { background: #eee; } th, td { text-align: center; }

 <div id="result"></div>

Answer 13

Not sure about the subelements, but all browsers should support this now:

for (val of lineChartData) {
  document.write(val);
}

This might give you some ideas For-each over an array in JavaScript?