Template string, can contain multiline content
wrap it in backticks (') and add a newline, to span across two lines
var normalString = `line1 //// line3`;
assert.equal(normalString, 'line1\n\nline3');
even over more than two lines
var multiline = ``;
assert.equal(multiline.split('\n').length, 4);
and expressions inside work too
like simple variables
var x = 42;
var multiline = `line 1 $ {x}`;
assert.equal(multiline, 'line 1\n\n 42');
also here spaces matter
var x = 42;
var multiline = ``;
assert.equal(multiline, '\n\n42');
Links
mdn
docs
Description of multiline template strings.