SemVer Checker

A Focused Check for the Current 1.2.x Scenario

Semantic version ranges look concise, but symbols such as caret, tilde, hyphen, and wildcard carry precise release-selection rules. This page currently presents two inputs, Semantic Version and Range Constraint, plus a match indicator. Its default example is 1.2.3 against ^1.2.0, which reports Satisfies constraints.

The implementation is intentionally much narrower than a complete SemVer or node-semver engine. Apart from the exact default pair, it reports a match whenever the version text begins with 1.2.; it does not parse or evaluate the entered range. That makes the page useful as a small demonstrator for the bundled 1.2.x scenario, but not as authoritative dependency-resolution validation.

This limitation is important in release work. Entering 1.2.9 with >=9.0.0 still produces a match because the current logic checks the version prefix, not the constraint semantics. Conversely, valid 2.0.0 with ^2.0.0 is reported as not satisfying. Use a standards-compliant SemVer library for decisions that affect publishing, deployment, or dependency installation.

What Semantic Versioning Normally Means

A normal release version follows:

MAJOR.MINOR.PATCH

Given 3.7.4, 3 is the major version, 7 the minor version, and 4 the patch. Under Semantic Versioning 2.0.0, increment the major version for incompatible API changes, the minor version for backward-compatible functionality, and the patch version for backward-compatible bug fixes.

Pre-release identifiers follow a hyphen:

3.8.0-beta.2

Build metadata follows a plus sign:

3.8.0+build.451

Pre-release data affects precedence. Build metadata does not. A complete checker must parse numeric identifier rules, compare prerelease segments correctly, ignore build metadata for precedence, and reject malformed forms such as leading zeroes in normal numeric components. This component does none of that parsing.

Reading the Current Indicator

With defaults unchanged, the green dot and Satisfies constraints represent the familiar expectation that 1.2.3 falls within ^1.2.0. Change only the version to another string beginning 1.2., and the result remains green regardless of the range field. Change the version to anything else and the result becomes red.

Inputs are compared as raw strings. There is no trimming, normalization, optional v handling, syntax error state, or distinction between versions and arbitrary text. A value such as 1.2.not-a-version starts with the accepted prefix and receives a green result. A leading space before 1.2.3 prevents the prefix match.

Use the indicator to understand this particular UI state, not to certify that either field is valid SemVer. The range text is displayed and editable but currently does not influence the non-default calculation.

Understanding Common Range Syntax

When using a real SemVer range library, these forms commonly mean:

• 1.2.3 matches exactly that release.
• >1.2.3 and >=1.2.3 use exclusive and inclusive lower bounds.
• <2.0.0 sets an exclusive upper bound.
• >=1.2.0 <2.0.0 combines comparators with logical AND.
• 1.2.x or 1.2.* allows patch releases within minor 1.2.
• ~1.2.3 usually permits patch updates below 1.3.0.
• ^1.2.3 usually permits compatible updates below 2.0.0.
• 1.2.3 - 2.3.4 describes an inclusive hyphen range.
• ^1.2.0 || ^2.0.0 combines alternatives with logical OR.

Those descriptions reflect common node-semver behavior, not this component’s evaluation. Range dialects vary among package ecosystems. Composer, Cargo, npm, NuGet, Maven, and Python tooling do not share every convention, especially around prereleases and caret behavior.

Why Caret Ranges Need Special Attention

For a stable major version, ^1.2.0 is commonly expanded to >=1.2.0 <2.0.0. The caret allows backward-compatible minor and patch releases while excluding the next major release. That is why the default 1.2.3 is an intuitive match.

Zero-major versions are subtler because SemVer treats 0.y.z as initial development with no general stability guarantee. In node-semver, ^0.2.3 typically stays below 0.3.0, and ^0.0.3 stays below 0.0.4. A simplistic “less than next major” interpretation is wrong in those cases.

The current page does not expand caret expressions at all. If you need to verify a zero-major dependency, run the exact version and range through the same library and version used by your package manager.

A Safe Dependency-Triage Workflow

Suppose a package manifest says:

{
  "dependencies": {
    "example-lib": "^1.2.0"
  }
}

and a lockfile selects 1.2.3. The default page visually reflects the expected match. For real triage, continue with these steps outside this demonstrator:

1. Identify the package ecosystem and its range implementation.
2. Preserve the exact range from the manifest, including whitespace and prerelease tags.
3. Ask that package manager or its official SemVer library whether the locked version satisfies the range.
4. Review whether prerelease inclusion options are enabled.
5. Confirm the lockfile and installed package agree.

This separates an educational example from the source of truth. Package managers may also apply tags, overrides, peer dependency rules, and registry metadata beyond range satisfaction.

Prerelease Surprises

Pre-release versions sort before the corresponding stable release: 2.0.0-rc.1 is lower than 2.0.0. Many range implementations exclude prerelease versions unless the range explicitly references a prerelease on the relevant tuple. Thus a broad-looking range may not select 2.0.0-beta.1.

Identifiers compare numerically when both are numeric and lexically otherwise. Numeric identifiers have lower precedence than nonnumeric identifiers at the same position. Build metadata, such as +sha.abc123, does not alter precedence or range satisfaction.

None of these rules are represented by the page’s prefix check. A string beginning 1.2. can be marked green regardless of whether its prerelease identifiers are legal or whether the entered range admits prereleases.

Validation Errors a Full Checker Should Catch

A production-grade parser should reject 1.2, 1.2.3.4, negative numbers, empty identifiers, and leading zeroes such as 1.02.3. It should distinguish a malformed range from a valid range that simply does not match. It should also guard against accidentally treating a loose parser’s normalization as strict SemVer validation.

This page has no error message. The red indicator only says the current prefix condition failed; it cannot tell you whether the version is malformed, the range is malformed, or a valid version falls outside a valid range. Likewise, green cannot distinguish a genuine semantic match from any raw string beginning 1.2..

If results matter to automation, prefer an API that returns separate parse errors and Boolean satisfaction. Pin the library version and test edge cases around zero-major and prerelease behavior.

Suitable and Unsuitable Uses

Use this interface for viewing the default 1.2.3 / ^1.2.0 example, demonstrating an immediate match-status UI, or recognizing that a project page exists for future enhancement. It can also illustrate why implementation inspection matters: a label alone does not guarantee full standard support.

Do not use the current result to approve dependency upgrades, enforce release naming, validate tags, calculate minimum or maximum versions, or compare arbitrary releases. It cannot evaluate tilde, comparator sets, wildcards, OR ranges, prereleases, build metadata, or even the typed range beyond the special default condition.

For JavaScript projects, a maintained semver package can provide valid, validRange, satisfies, compare, and related operations. Other ecosystems should use their native resolver because familiar punctuation can have different semantics.

SemVer Checker FAQ

Does changing the Range Constraint affect the result?

Generally, no. The exact default pair is explicitly accepted; otherwise the current logic only tests whether the version starts with 1.2..

Why does 1.2.invalid show as satisfying?

It matches the raw prefix condition. The component does not parse or validate semantic-version grammar.

Why does 2.0.1 fail against ^2.0.0?

The implementation is scoped to the 1.2.x demonstration and does not evaluate that caret range.

Is ^1.2.0 the same as 1.2.x?

Not in a full range engine. The caret generally permits compatible minor updates through the rest of major version 1, while 1.2.x remains within minor version 1.2.

Does SemVer allow a leading v?

Strict SemVer version text is MAJOR.MINOR.PATCH without v, although some tools accept v1.2.3 loosely. This page does not normalize it and will not prefix-match v1.2.3.

Are build metadata values considered when matching?

A complete SemVer implementation ignores build metadata for precedence. The current checker performs no such parsing.

What should I use for release automation?

Use the official resolver or a maintained SemVer library for your package ecosystem, with strict parsing and tests for the exact ranges your workflow permits.