[Home](./index.md) > [kibana-plugin-plugins-expressions-server](./kibana-plugin-plugins-expressions-server.md) > [ExpressionAstExpressionBuilder](./kibana-plugin-plugins-expressions-server.expressionastexpressionbuilder.md) > [toAst](./kibana-plugin-plugins-expressions-server.expressionastexpressionbuilder.toast.md) ## ExpressionAstExpressionBuilder.toAst property Converts expression to an AST. `ExpressionAstExpression` Signature: ```typescript toAst: () => ExpressionAstExpression; ```