How to fix Enum member name must be followed by ',' ':' or '}' in TypeScript

What this error means

The "Enum member name must be followed by ',' ':' or '}'" error (TS1357) indicates that TypeScript encountered an invalid character immediately after an enum member name. TypeScript has strict syntax rules for enum declarations: each member must be followed by one of three characters: 1. A comma (,) to separate it from the next member 2. An equals sign (=) to assign a specific value to that member 3. A closing brace (}) to end the enum declaration This error most frequently occurs when developers accidentally use a colon (:) instead of an equals sign (=) when assigning values to enum members. This mistake is particularly common for those coming from languages like Python or for those who confuse enum syntax with object literal or type annotation syntax. The error message was specifically improved in TypeScript to explicitly mention the closing brace (}) as an acceptable character, making it clearer what valid options exist at that position in the enum definition.

Typical symptoms

• Compilation fails with TS1357 error message
• IDE shows red squiggly line after enum member name
• Error points to a specific character after an enum member
• Code works in JavaScript-like syntax but fails in TypeScript strict parsing
• Syntax highlighting appears broken in enum declaration
• Build process stops at enum definition file

Common causes

1. Using a colon (:) instead of equals sign (=) when assigning enum values
2. Missing comma between consecutive enum members
3. Using semicolon (;) instead of comma (,) to separate members
4. Including illegal characters or operators after member name
5. Adding type annotations to enum members (not allowed)
6. Attempting to use object literal syntax inside enum declaration
7. Copy-pasting code from a different syntax context (objects, interfaces)
8. Trailing characters or typos immediately after member name

How to fix "Enum member name must be followed by ',' ':' or '}'"

// WRONG - uses colon (:)
enum Status {
  Active: 1,      // ❌ Error: expected ',' '=' or '}'
  Inactive: 0,
  Pending: 2
}

// CORRECT - uses equals sign (=)
enum Status {
  Active = 1,     // ✅ Valid syntax
  Inactive = 0,
  Pending = 2
}

// WRONG - missing commas
enum Color {
  Red = "#FF0000"
  Green = "#00FF00"    // ❌ Error: expected ','
  Blue = "#0000FF"
}

// WRONG - using semicolons
enum Color {
  Red = "#FF0000";     // ❌ Error: expected ','
  Green = "#00FF00";
  Blue = "#0000FF"
}

// CORRECT - commas between members
enum Color {
  Red = "#FF0000",     // ✅ Valid
  Green = "#00FF00",
  Blue = "#0000FF"     // Trailing comma is optional
}

// WRONG - type annotations not allowed
enum HttpStatus {
  OK: number = 200,           // ❌ Error
  NotFound: number = 404,
  ServerError: number = 500
}

// CORRECT - no type annotations needed
enum HttpStatus {
  OK = 200,                   // ✅ TypeScript infers the type
  NotFound = 404,
  ServerError = 500
}

// WRONG - various string enum mistakes
enum Direction {
  North: "N",        // ❌ Colon instead of equals
  East = "E"
  South = "S",       // ❌ Missing comma after East
  West: 'W'          // ❌ Colon instead of equals
}

// CORRECT - proper string enum
enum Direction {
  North = "N",       // ✅ Equals sign + comma
  East = "E",
  South = "S",
  West = "W"
}

// WRONG - missing initializer
enum Direction {
  North,             // ❌ String enums need explicit values
  East = "E",
  South = "S"
}

// CORRECT - all members initialized
enum Direction {
  North = "N",
  East = "E",
  South = "S",
  West = "W"
}

// WRONG - various illegal characters
enum Priority {
  Low = 1,
  Medium = 2 + 1,    // ✅ Computed values are allowed
  High:: 3,          // ❌ Double colon invalid
  Critical = = 4,    // ❌ Double equals invalid
  Urgent! = 5        // ❌ Exclamation mark invalid
}

// CORRECT - only valid syntax
enum Priority {
  Low = 1,
  Medium = 2,
  High = 3,
  Critical = 4,
  Urgent = 5
}

// Auto-increment (no assignment needed)
enum Level {
  Beginner,          // = 0 (automatic)
  Intermediate,      // = 1 (auto-increment)
  Advanced          // = 2 (auto-increment)
}

// Explicit numbering
enum Level {
  Beginner = 1,      // Start at 1
  Intermediate,      // = 2 (auto-increment)
  Advanced          // = 3 (auto-increment)
}

// Computed values
enum Permission {
  None = 0,
  Read = 1 << 0,     // = 1
  Write = 1 << 1,    // = 2
  Execute = 1 << 2   // = 4
}

// WRONG - mixing requires initialization
enum Mixed {
  First = "first",
  Second,            // ❌ Error: must initialize after string member
  Third = 3
}

// CORRECT - explicit initialization
enum Mixed {
  First = "first",
  Second = "second", // ✅ All string members initialized
  Third = "third"
}

Advanced notes

// Object literal - uses colons
const statusObject = {
  active: 1,      // Colon for key-value pairs
  inactive: 0
};

// Enum - uses equals signs
enum StatusEnum {
  Active = 1,     // Equals for member assignments
  Inactive = 0
}

// WRONG
const enum Mode {
  Dev: "development",    // ❌ Colon not allowed
  Prod: "production"
}

// CORRECT
const enum Mode {
  Dev = "development",   // ✅ Equals sign
  Prod = "production"
}

// Allowed but not recommended
enum Mixed {
  Yes = 1,
  No = "NO",
  Maybe = 2
}

// In a .d.ts file
declare enum ExternalEnum {
  First = 1,     // Still uses equals, not colon
  Second = 2
}

// Before (JavaScript object)
const Status = {
  ACTIVE: 'active',
  INACTIVE: 'inactive'
};

// After (TypeScript enum) - note the syntax change
enum Status {
  ACTIVE = 'active',      // Colon → Equals
  INACTIVE = 'inactive'
}

const Status = {
  ACTIVE: 'active',
  INACTIVE: 'inactive'
} as const;

type StatusValue = typeof Status[keyof typeof Status];

Frequently asked questions

What does "TS1357" mean?

The "Enum member name must be followed by ',' ':' or '}'" error (TS1357) indicates that TypeScript encountered an invalid character immediately after an enum member name. TypeScript has strict syntax rules for enum declarations: each member must be followed by one of three characters: 1. A comma (,) to separate it from the next member 2.

How do I fix "TS1357"?

This TypeScript syntax error occurs when an enum member declaration is followed by an invalid character or separator. The most common cause is using a colon (:) instead of an equals sign (=) when assigning values, or forgetting a comma between members.

What causes "TS1357"?

Using a colon (:) instead of equals sign (=) when assigning enum values Missing comma between consecutive enum members Using semicolon (;) instead of comma (,) to separate members

Is the "TS1357" error serious?

It is a medium-severity error — more of a blocker than a risk. The steps above resolve it.

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Official resources & further reading

• 📚TypeScript Official Documentation
• 📖
  TypeScript Handbook - Enums(Official Docs)
• TypeScript Contribution Diary: Improved Syntax Error for Enum Member Colons
• 🐙
  TypeScript Issue #838 - More helpful error message for mistakenly using : instead of =(GitHub)
• DigitalOcean - How To Use Enums in TypeScript
• TypeScript Tutorial - TypeScript Enum
• Refine - A Detailed Guide on TypeScript Enum with Examples
• Stack Overflow - TypeScript Enums Questions