Inline Expressions

Inline Expressions let you dynamically generate and manipulate values using the {{...}} syntax. Use them in variables, headers, bodies, scripts, and other places where values are expected.

Grammar 

expression       := literal | variable | functionCall | operation | array
literal          := "double-quoted string" | 'single-quoted string' | number | boolean | null
variable         := identifier | variable.property | variable[index]
functionCall     := functionName [ "(" [expression[, expression]*] ")" ]
operation        := expression operator expression
array            := "[" [expression[, expression]*] "]"
operator         := "+" | "-" | "*" | "/" | "??"

Expression Types

Literals

  • Strings: Single or double-quoted
    {{"Hello"}}, {{'World'}}
  • Numbers: Integers or decimals
    {{123}}, {{45.67}}
  • Booleans: {{true}}, {{false}}
  • Null: {{null}}

Variables

Access variables using dot notation or brackets:
Examples: {{myVar}}, {{user.name}}, {{users[0].role}}

Arrays

Define arrays with square brackets. Elements can include literals, variables, functions, and nested expressions:
Examples:

  • {{[1, 2, 3]}}
  • {{["admin", "user", $randomEmail()]}}
  • {{[myVar, $randomInt(1, 10) * 5]}}

Function Calls

  • Without arguments: {{$randomEmail}} or {{$randomEmail()}}
  • With arguments: {{$pickOne(["admin", "user"])}}
  • Nested calls: {{$randomInt($randomInt(1, 5), 100)}}

Operations

  • Arithmetic: {{5 + myIntVar * $randomInt(1, 10)}}
  • String concatenation: {{"User: " + $randomUserName}}
  • Coalesce (??): Returns right value if left is null or errors
    Example: {{token ?? $eval("getToken()")}}

Using Inline Expressions in Scripts

Inline expressions can be evaluated directly from scripts using the same syntax as variables. Use jc.variables.get to resolve an inline expression dynamically:

// Evaluate an arithmetic expression with random values
const result = jc.variables.get("123 + myVar + $randomInt(1, 10)");
console.log(result);

// Prompt the user for input and use it in the script
const userNumber = jc.variables.get("$intInput('Enter a number')");
console.log(`User entered: ${userNumber}`);

Built-In Functions

JetClient provides a comprehensive set of built-in functions for generating random values, collecting user input, reading files, executing JavaScript, and running shell commands. For the complete list, see Functions.

VariablesFunctions