Can't use array.map in short expression?

Valerian_Lebert · July 4, 2023, 1:29pm

Hi there

Am I missing something ?
For some reason I can’t use array.map in short expressions. Is this normal behaviour ?

jan · July 4, 2023, 2:22pm

That is sadly a known issue:

github.com/n8n-io/n8n

$evaluateExpression cannot handle arrow function or inner function

opened 05:20PM - 25 Feb 21 UTC

nantoniazzi

**Describe the bug** I'm trying to use arrow function in some expressions (I wa…nt to filter elements of my previous node) but I always get an error. I tried to reproduce it in a Function node. ``` javascript const data = $evaluateExpression('{{ [1, 2, 3, 4, 5].filter(v => v > 2).join(`,`) }}') ``` **error**: *"Expression is not valid: Malformed arrow function parameter list"* it doesn't work for anonymous function either ``` javascript const data = $evaluateExpression('{{ [1, 2, 3, 4, 5].filter(function(v) { return v > 2}).join(`,`) }}') ``` **error**: *"Expression is not valid: missing ) after argument list"* I thought it was related to the riot template engine, but I have not the problem executing those expressions in a standalone riot template installation. **To Reproduce** Run this node: ``` { "nodes": [ { "parameters": { "functionCode": "const data = $evaluateExpression('{{ [1, 2, 3, 4, 5].filter(v => v > 2).join(`,`) }}')\nreturn [{json: {value: data} }];" }, "name": "DEBUG", "type": "n8n-nodes-base.function", "typeVersion": 1, "position": [ 440, 300 ] } ], "connections": {} } ``` **Expected behavior** The Function node should returns ``` [{json: {value: '3,4,5'}] ``` instead it raises an error **Environment (please complete the following information):** - n8n Version 0.108.0 - Node.js Version v14.15.5

We are currently in the process of replacing that library with an own one which should then solve that issue.

Valerian_Lebert · July 4, 2023, 2:35pm

Any workaround (I am no JS expert…).

I used function/code node but maybe a more simple workaround ?

Jon · July 4, 2023, 2:36pm

@Valerian_Lebert code node is the best option at the moment.

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Can't use array.map in short expression?

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