Package Export Condition Priority Tool

Description

Select the first matching export-condition key.

Package and container references combine names, selectors, conditions and platform metadata. A restricted lexical split can preserve these parts without validating registry identity, available targets, dependency graphs or runtime resolution.

Select the first matching export-condition key.

When to use this tool

Use Package Export Condition Priority when checking the stated package, Cargo or container-reference component.

How to use the tool and how it works

Enter conditionKeys, activeConditions. Keep parallel arrays aligned. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read matched, selectedKey, index. Inspect matched before interpreting the associated values.

Select the first matching export-condition key. Require unique conditionKeys; scan input order for default or membership in activeConditions, returning matched/key/index or empty key and -1.^[1]

Input field	Meaning and units	Accepted input
conditionKeys	Condition Keys	Required. Array of text; maximum UTF-16 length 8192; maximum items 256.
activeConditions	Active Conditions	Required. Array of text; maximum UTF-16 length 8192; maximum items 256.

Output field	Interpretation	Returned shape
matched	Whether a default or active key was encountered; no actual package export target is resolved.	Required. Boolean.
selectedKey	Selected Key	Required. Text; maximum UTF-16 length 8192.
index	First matching supplied condition key, or -1 if none; ordering follows conditionKeys.	Required. Safe integer.

json

{
  "input": {
    "conditionKeys": [
      "import",
      "node",
      "default"
    ],
    "activeConditions": [
      "node",
      "import"
    ]
  },
  "output": {
    "matched": true,
    "selectedKey": "import",
    "index": 0
  }
}

Limitations and assumptions

The tool does not resolve targets, nested conditions or actual runtime module exports.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.

Alternative or Complementary methods

Use the relevant package manager, runtime or registry against the actual project for complete resolution and validation.

References

Calculation and input contract: development/package-export-condition-priority — tool.io

Similar or alternative tools

Package JSON Export Condition Key
Inspect one package export-condition key under a restricted rule.
npm Package Tag Selector Split
Split a package selector at its required name-selector boundary.