JavaScript equivalent of Python's format() function?

Question

Python has this beautiful function to turn this:

bar1 = \'foobar\'
bar2 = \'jumped\'
bar3 = \'dog\'

foo = \'The lazy \' + bar3 + \' \' + bar2 \' over the \'         


        

Answer 1

tl;dr

foo = (a, b, c) => `The lazy ${a} ${b} over the ${c}`

Why template strings alone aren't enough

ES6 template strings provide a feature quite similar to pythons string format. However, you have to know the variables before you construct the string:

var templateString = `The lazy ${bar3} ${bar2} over the ${bar1}`;

Why format?

Python's str.format allows you to specify the string before you even know which values you want to plug into it, like:

foo = 'The lazy {} {} over the {}'

bar1 = 'foobar'
bar2 = 'jumped'
bar3 = 'dog'

foo.format(bar3, bar2, bar1)

Solution

With an arrow function, we can elegantly wrap the template string for later use:

foo = (a, b, c) => `The lazy ${a} ${b} over the ${c}`

bar1 = 'foobar';
bar2 = 'jumped';
bar3 = 'dog';

foo(bar3, bar2, bar1)

Of course this works with a regular function as well, but the arrow function allows us to make this a one-liner. Both features are available in most browsers und runtimes:

• Can I use template literals?
• Can I use arrow functions?