How do you write backticks in javascript?
Template literals are literals delimited with backtick ( Template literals are sometimes informally called template strings, because they are used most commonly for string interpolation (to create strings by doing substitution of
placeholders). However, a tagged template literal may not result in a string; it can be used with a custom tag function to perform whatever operations you want on the different parts of the template literal. Parameters
The string text that will become part of the template literal. Almost all characters are allowed literally, including line breaks and other whitespace characters. However, invalid escape sequences will cause a syntax error, unless a tag function is used. expression An expression to be inserted in the current position, whose value is converted to a string or passed to tagFunction If specified, it will be called with the template strings array and substitution expressions, and the return value becomes the value of the template literal. See tagged templates. DescriptionTemplate literals are enclosed
by backtick ( Along with having normal strings, template literals can also contain other parts called placeholders, which are embedded expressions delimited by a dollar sign and curly braces: To supply a function of your own, precede the template literal with a function name; the result is called a tagged template. In that case, the template literal is passed to your tag function, where you can then perform whatever operations you want on the different parts of the template literal. To escape a backtick in a template literal, put a backslash (
Dollar signs can be escaped as well to prevent interpolation.
Multi-line stringsAny newline characters inserted in the source are part of the template literal. Using normal strings, you would have to use the following syntax in order to get multi-line strings:
Using template literals, you can do the same with this:
String interpolationWithout template literals, when you want to combine output from
expressions with strings, you'd concatenate them using the addition operator
That can be hard to read – especially when you have multiple expressions. With template literals, you can avoid the concatenation operator
— and improve the readability of your code — by using placeholders of the form
Note that there's a mild difference between the two syntaxes. Template literals coerce their expressions directly to strings, while addition coerces its operands to primitives first. For more
information, see the reference page for the Nesting templatesIn certain cases, nesting a
template is the easiest (and perhaps more readable) way to have configurable strings. Within a backtick-delimited template, it is simple to allow inner backticks by using them inside an For example, without template literals, if you wanted to return a certain value based on a particular condition, you could do something like the following:
With a template literal but without nesting, you could do this:
With nesting of template literals, you can do this:
Tagged templatesA more advanced form of template literals are tagged templates. Tags allow you to parse template literals with a function. The first argument of a tag function contains an array of string values. The remaining arguments are related to the expressions. The tag function can then perform whatever operations on these arguments you wish, and return the manipulated string. (Alternatively, it can return something completely different, as described in one of the following examples.) The name of the function used for the tag can be whatever you want.
The tag does not have to be a plain identifier. You can use any expression with precedence greater than 16, which includes property access, function call, new expression, or even another tagged template literal.
While technically permitted by the syntax, untagged template literals are strings and will throw a
The only exception is optional chaining, which will throw a syntax error.
Note that these two expressions are still parsable. This means they would not be subject to automatic semicolon insertion, which will only insert semicolons to fix code that's otherwise unparsable.
Tag functions don't even need to return a string!
The first argument received by the tag function is an array of strings. For any template literal, its
length is equal to the number of substitutions (occurrences of For any particular tagged template literal expression, the tag function will always be called with the exact same literal array, no matter how many times the literal is evaluated.
This allows the tag to cache the result based on the identity of its first argument. To further ensure the array value's stability, the first argument and its
Raw stringsThe special
In addition, the
This is useful for many tools which give special treatment to literals tagged by a particular name.
Tagged templates and escape sequencesIn normal template literals, the escape sequences in string literals are all allowed. Any other non-well-formed escape sequence is a syntax error. This includes:
Note: However, this is problematic for tagged templates, which, in addition to the "cooked" literal, also have access to the raw literals (escape sequences are preserved as-is). Tagged templates should allow the embedding of languages (for example DSLs, or LaTeX), where other escapes sequences are common. Therefore, the syntax restriction of well-formed escape sequences is removed from tagged templates.
However, illegal escape sequences must still be represented in the "cooked" representation. They will show up as
Note that the escape-sequence restriction is only dropped from tagged templates, but not from untagged template literals:
Specifications
Browser compatibilityBCD tables only load in the browser See alsoWhat is the backtick in JavaScript?Backticks are an ES6 feature that allows you to create strings in JavaScript. Although backticks are mostly used for HTML or code embedding purposes, they also act similar to single and double quotes. Besides, using backticks makes it easier for string operations.
How do you use a backtick?To create a back quote using a U.S. keyboard, press the ` , which is located directly below the Esc key. This key is also used for typing the tilde ( ~ ) character if the Shift key is held while it is pressed.
Can you do string interpolation in JavaScript?String interpolation in JavaScript is a process in which an expression is inserted or placed in the string. To insert or embed this expression into the string a template literal is used. By using string interpolation in JavaScript, values like variables and mathematical expressions and calculations can also be added.
What is ${} called in JavaScript?${} is a placeholder that is used in template literals. You can use any valid JavaScript expression such as variable, arithmetic operation, function call, and others inside ${}. The expression used inside ${} is executed at runtime, and its output is passed as a string to template literals.
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