Composition

Composition

Query composition

In JSONata, everything is an _expression_. An expression comprises _values_, _functions_ and _operators_ which, when _evaluated_, produces a resulting value. Functions and operators are applied to values which themselves can be the results of evaluating sub-expressions. In that way, the language is fully _composable_ to any level of complexity.

Parenthesized expressions and blocks

Used to override the operator precedence rules. E.g.

  • (5 + 3) * 4

Used to compute complex expressions on a context value

  • Product.(Price * Quantity) - both Price and Quantity are properties of the Product object

Used to support 'code blocks' - multiple expressions, separated by semicolons

  • (expr1; expr2; expr3)

Each expression in the block is evaluated _in sequential order_; the result of the last expression is returned from the block.


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