Expressions are a feature of Angular. They are a subset of JavaScript commands in addition to some Angular function. Expressions are used in many places in Angular. For example, anytime you bind data, you can use an expression. This makes understanding expressions important.
An expression will be evaluated to a value, to a true statement, to a function in scope, or to a variable in scope. This makes them powerful, but they do have some limitations.
You can use some JavaScript, but not all JavaScript in an expression. Here are some of the things that you can and cannot do in JavaScript using expressions:
You can use a string, number, Boolean, array literal, or object literal
You can use any operators, for example,
a + b,a && b, ora || bYou can access properties on an object or look up values in an array
You can make function calls
You cannot use flow control statements in an expression, for example, an
ifstatement