[Home](./index.md) > [kibana-plugin-plugins-expressions-server](./kibana-plugin-plugins-expressions-server.md) > [ExpressionAstFunctionBuilder](./kibana-plugin-plugins-expressions-server.expressionastfunctionbuilder.md) > [toString](./kibana-plugin-plugins-expressions-server.expressionastfunctionbuilder.tostring.md) ## ExpressionAstFunctionBuilder.toString property Converts function to an expression string. `string` Signature: ```typescript toString: () => string; ```