# Expressions Expressions are parts of the document that are evaluated as JavaScript code. The result of the expression is converted to a string and injected into the document. Expressions usually use [variables or functions](identifiers.md). ## Basic syntax Expressions start with `${` and end with `}`. A simple expression: Hello, ${ name }! with a data object of `{ name: 'world' }` will result in: Hello, world! Note that whitespace within an expression is ignored (just like regular JavaScript), but whitespace outside the expression is significant: Hello, ${name } ! with a data object of `{ name: 'world' }` will result in: Hello, world ! ## Escaping By default, the expression's value is escaped (using [lodash's `escape`](https://lodash.com/docs#escape)): Hello, ${ name }! with a data object of `{ name: '' }` will result in: Hello, <html>! If you want to prevent escaping, use the [built-in `raw` function](identifiers.md#raw): Hello, ${ raw(name) }! with a data object of `{ name: '' }` will result in: Hello, ! ## Caveats Expressions are not interpreted by ARC templates; they are only evaluated. This means that *an expression may not contain `}`*. For example, this template: ${ 'test of }' } will result in a syntax error when the template is compiled, because the template attempts to treat `'test of ` as an expression. This also means you can't use IIFEs as expressions.