Comparing Pre-release Versions (alpha, beta, rc)

Comparing Pre-release Versions

Pre-release versions follow specific ordering rules defined in the SemVer 2.0.0 specification. These rules are critical when you publish alpha, beta, and RC releases.

The Ordering Algorithm

When comparing two pre-release versions with the same major.minor.patch:

1. Split the pre-release part by dots into identifiers
2. Compare identifiers left to right
3. Apply type-specific rules for each pair

Type-Specific Rules

Type A	Type B	Rule
Number	Number	Compare as integers (2 < 11)
String	String	Compare lexically ("alpha" < "beta")
Number	String	Number is always lower (1 < "alpha")

Complete Ordering Example

1.0.0-0           (numeric: 0)
1.0.0-1           (numeric: 1)
1.0.0-alpha       (string: "alpha")
1.0.0-alpha.0     (string + numeric: "alpha".0)
1.0.0-alpha.1     (string + numeric: "alpha".1)
1.0.0-alpha.beta  (string + string: "alpha"."beta")
1.0.0-beta        (string: "beta")
1.0.0-beta.2      (string + numeric: "beta".2)
1.0.0-beta.11     (string + numeric: "beta".11)
1.0.0-rc.1        (string + numeric: "rc".1)
1.0.0             (release — always highest)

Common Gotchas

Gotcha 1: "11" > "2" but 11 > 2 too (same result, different reasons)

• If identifiers are numeric strings ("11" and "2"), they are compared as integers
• So beta.11 > beta.2 — this is correct and intuitive

Gotcha 2: "alpha" > 1

• String identifiers always have higher precedence than numeric ones
• So 1.0.0-alpha > 1.0.0-1

Gotcha 3: Longer > Shorter (when prefix is equal)

• 1.0.0-alpha.1 > 1.0.0-alpha
• The additional identifier gives it higher precedence

Practical Release Cycle

A typical release cycle might be:

1.0.0-alpha.1 → 1.0.0-alpha.2 → 1.0.0-beta.1 → 1.0.0-rc.1 → 1.0.0