Implementation:Langgenius Dify Var Utils

Knowledge Sources	Langgenius_Dify
Domains	Frontend, Utilities
Last Updated	2026-02-12 07:00 GMT

Overview

Provides variable management utilities for prompt templates and workflows, including variable creation, key validation, template extraction, and URL construction.

Description

This module is a central utility for working with template variables across the Dify frontend. getNewVar creates a new prompt variable from a key and type using a default template. getNewVarInWorkflow creates workflow-specific InputVar instances with workflow-appropriate defaults. checkKey validates a single variable key against naming rules (non-empty, max length, alphanumeric/underscore only, must not start with a digit), returning a typed i18n error message key on failure. checkKeys batch-validates an array of keys, stopping at the first error. hasDuplicateStr detects duplicate strings in an array. getVars extracts Template:Variable name placeholders from a prompt template string, filtering out reserved system placeholders (context, history, query, pre_prompt) and deduplicating results. The module also exports basePath (the application base path from environment configuration), getMarketplaceUrl for constructing marketplace URLs with tracking parameters, and replaceSpaceWithUnderscoreInVarNameInput for live input normalization that preserves cursor position.

Usage

Use these utilities when building or validating prompt templates, creating new variables in the app debug panel or workflow editor, constructing marketplace links, or normalizing variable name input fields.

Code Reference

Source Location

Repository: Langgenius_Dify
File: web/utils/var.ts
Lines: 1-155

Signature

export const getNewVar = (key: string, type: string) => PromptVariable

export const getNewVarInWorkflow = (key: string, type?: InputVarType) => InputVar

export type VarKeyErrorMessageKey = I18nKeysByPrefix<'appDebug', 'varKeyError.'>

export const checkKey = (
  key: string,
  canBeEmpty?: boolean,
  _keys?: string[],
) => true | VarKeyErrorMessageKey

export const checkKeys = (
  keys: string[],
  canBeEmpty?: boolean,
) => CheckKeysResult

export const hasDuplicateStr = (strArr: string[]) => boolean

export const getVars = (value: string) => string[]

export const basePath: string

export function getMarketplaceUrl(
  path: string,
  params?: Record<string, string | undefined>,
): string

export const replaceSpaceWithUnderscoreInVarNameInput = (
  input: HTMLInputElement,
) => void

Import

import {
  getNewVar,
  getNewVarInWorkflow,
  checkKey,
  checkKeys,
  hasDuplicateStr,
  getVars,
  basePath,
  getMarketplaceUrl,
  replaceSpaceWithUnderscoreInVarNameInput,
} from '@/utils/var'

I/O Contract

Inputs (getNewVar)

Name	Type	Required	Description
key	`string`	Yes	The variable key identifier
type	`string`	Yes	The variable type (e.g., "string", "number", "select")

Inputs (getNewVarInWorkflow)

Name	Type	Required	Description
key	`string`	Yes	The variable key identifier
type	`InputVarType`	No (default: textInput)	The workflow input variable type

Inputs (checkKey)

Name	Type	Required	Description
key	`string`	Yes	The variable key to validate
canBeEmpty	`boolean`	No	Whether an empty key is allowed
_keys	`string[]`	No	Reserved parameter (currently unused)

Inputs (checkKeys)

Name	Type	Required	Description
keys	`string[]`	Yes	Array of variable keys to validate
canBeEmpty	`boolean`	No	Whether empty keys are allowed

Inputs (getVars)

Name	Type	Required	Description
value	`string`	Yes	A prompt template string potentially containing `Template:Variable` placeholders

Inputs (getMarketplaceUrl)

Name	Type	Required	Description
path	`string`	Yes	The marketplace path segment
params	undefined>	No	Additional query parameters to append

Outputs

Function	Type	Description
getNewVar	`PromptVariable`	A new variable object populated from `VAR_ITEM_TEMPLATE` with the given key and type
getNewVarInWorkflow	`InputVar`	A new workflow input variable populated from `VAR_ITEM_TEMPLATE_IN_WORKFLOW`
checkKey	VarKeyErrorMessageKey	`true` if valid; otherwise an i18n error message key string
checkKeys	`CheckKeysResult`	Object with `isValid`, `errorKey`, and `errorMessageKey` fields
hasDuplicateStr	`boolean`	`true` if any string appears more than once in the array
getVars	`string[]`	Deduplicated array of variable names extracted from the template, excluding system placeholders
getMarketplaceUrl	`string`	Full marketplace URL with source tracking and optional query parameters

Usage Examples

Extract Variables from a Prompt Template

import { getVars } from '@/utils/var'

const template = 'Hello {{user_name}}, your order {{order_id}} is ready. {{#context#}}'
const vars = getVars(template)
// ['user_name', 'order_id']  (context placeholder is excluded)

Validate a Variable Key

import { checkKey } from '@/utils/var'

checkKey('valid_key')      // true
checkKey('123invalid')     // 'notStartWithNumber'
checkKey('')               // 'canNoBeEmpty'
checkKey('a'.repeat(200))  // 'tooLong'
checkKey('invalid-key')    // 'notValid'

Create a New Variable for the Workflow Editor

import { getNewVarInWorkflow } from '@/utils/var'
import { InputVarType } from '@/app/components/workflow/types'

const newVar = getNewVarInWorkflow('user_email', InputVarType.textInput)
// { variable: 'user_email', label: 'user_email', type: InputVarType.textInput, placeholder: '', default: '', hint: '', ... }

Check for Duplicate Variable Names

import { hasDuplicateStr } from '@/utils/var'

hasDuplicateStr(['name', 'email', 'name'])  // true
hasDuplicateStr(['name', 'email', 'phone']) // false

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