const parse = require('./parse')
|
const eq = require('./eq')
|
|
const diff = (version1, version2) => {
|
if (eq(version1, version2)) {
|
return null
|
} else {
|
const v1 = parse(version1)
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const v2 = parse(version2)
|
const hasPre = v1.prerelease.length || v2.prerelease.length
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const prefix = hasPre ? 'pre' : ''
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const defaultResult = hasPre ? 'prerelease' : ''
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for (const key in v1) {
|
if (key === 'major' || key === 'minor' || key === 'patch') {
|
if (v1[key] !== v2[key]) {
|
return prefix + key
|
}
|
}
|
}
|
return defaultResult // may be undefined
|
}
|
}
|
module.exports = diff
|
