[Home](./index.md) > [kibana-plugin-plugins-expressions-public](./kibana-plugin-plugins-expressions-public.md) > [ExpressionAstExpressionBuilder](./kibana-plugin-plugins-expressions-public.expressionastexpressionbuilder.md) ## ExpressionAstExpressionBuilder interface Signature: ```typescript export interface ExpressionAstExpressionBuilder ``` ## Properties | Property | Type | Description | | --- | --- | --- | | [findFunction](./kibana-plugin-plugins-expressions-public.expressionastexpressionbuilder.findfunction.md) | <FnDef extends AnyExpressionFunctionDefinition = AnyExpressionFunctionDefinition>(fnName: InferFunctionDefinition<FnDef>['name']) => Array<ExpressionAstFunctionBuilder<FnDef>> | [] | Recursively searches expression for all ocurrences of the function, including in subexpressions.Useful when performing migrations on a specific function, as you can iterate over the array of references and update all functions at once. | | [functions](./kibana-plugin-plugins-expressions-public.expressionastexpressionbuilder.functions.md) | ExpressionAstFunctionBuilder[] | Array of each of the buildExpressionFunction() instances in this expression. Use this to remove or reorder functions in the expression. | | [toAst](./kibana-plugin-plugins-expressions-public.expressionastexpressionbuilder.toast.md) | () => ExpressionAstExpression | Converts expression to an AST. ExpressionAstExpression | | [toString](./kibana-plugin-plugins-expressions-public.expressionastexpressionbuilder.tostring.md) | () => string | Converts expression to an expression string. string | | [type](./kibana-plugin-plugins-expressions-public.expressionastexpressionbuilder.type.md) | 'expression_builder' | Used to identify expression builder objects. |