How can I add a variable to console.log?

问题

I'm making a simple game in JavaScript but in the story I need it to say the players name. so what I have so far is:

var name = prompt("what is your name?");

console.log("story" name "story);

how do I do the second line? or there is another way I could do this. Is it possible to have 2 console.log(); on 1 line in the console?

回答1:

Then use + to combine strings:

console.log("story " + name + " story");

回答2:

console.log takes multiple arguments, so just use:

console.log("story", name, "story");

If name is an object or an array then using multiple arguments is better than concatenation. If you concatenate an object or array into a string you simply log the type rather than the content of the variable.

But if name is just a primitive type then multiple arguments works the same as concatenation.

回答3:

You can use another console method:

var name = prompt("what is your name?");
console.log(`story ${name} story`);

回答4:

There are several ways of consoling out the variable within a string.

Method 1 :

console.log("story", name, "story");

Benefit : if name is a JSON object, it will not be printed as "story" [object Object] "story"

Method 2 :

console.log("story " + name + " story");

Method 3: When using ES6 as mentioned above

console.log(`story ${name} story`);

Benefit: No need of extra , or +

Method 4:

console.log('story %s story',name);

Benefit: the string becomes more readable.

回答5:

When using ES6 you can also do this:

var name = prompt("what is your name?");
console.log(`story ${name} story`);

Note: You need to use backticks `` instead of "" or '' to do it like this.

回答6:

You can pass multiple args to log:

console.log("story", name, "story");

回答7:

It depends on what you want.

console.log("story "+name+" story") will concatenate the strings together and print that. For me, I use this because it is easier to see what is going on.

Using console.log("story",name,"story") is similar to concatenation however, it seems to run something like this:

 var text = ["story", name, "story"];
 console.log(text.join(" "));

This is pushing all of the items in the array together, separated by a space: .join(" ")

回答8:

Both console.log("story" + name + "story") and console.log("story", name, "story") works just fine as mentioned in earlier answers.

I will still suggest of having a habit of console.log("story", name, "story"), because, if trying to print the object contents, like json object, having "story" + objectVariable + "story" will convert it into string.

This will have output like : "story" [object Object] "story".

Just a good practice.

回答9:

You can also use printf style of formatting arguments. It is available in at least Chrome, Firefox/Firebug and node.js.

var name = prompt("what is your name?");

console.log("story %s story", name);

It also supports %d for formatting numbers

回答10:

%j works for only Node.js. %j converts a value to a JSON string and inserts it.

console.log('%j new messages for', 7, 'john')
// 7 new messages for john

More string substitutions here:

https://exploringjs.com/impatient-js/ch_console.html

Docs:

Chrome: https://developers.google.com/web/tools/chrome-devtools/console/console-write#string_substitution_and_formatting
Firefox: https://developer.mozilla.org/en-US/docs/Web/API/Console#Using_string_substitutions
IE: https://docs.microsoft.com/en-gb/visualstudio/debugger/javascript-console-commands?view=vs-2019#ConsoleLog
Node.js: https://docs.microsoft.com/en-gb/visualstudio/debugger/javascript-console-commands?view=vs-2019#ConsoleLog
Spec: https://console.spec.whatwg.org/#formatter

回答11:

You can use the backslash to include both the story and the players name in one line.

var name=prompt("what is your name?"); console.log("story"\name\"story");

来源：https://stackoverflow.com/questions/16600925/how-can-i-add-a-variable-to-console-log

标签

javascript

console.log