24 lines
634 B
JavaScript
24 lines
634 B
JavaScript
const parse = require('./parse')
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const eq = require('./eq')
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const diff = (version1, version2) => {
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if (eq(version1, version2)) {
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return null
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} else {
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const v1 = parse(version1)
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const v2 = parse(version2)
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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) {
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if (key === 'major' || key === 'minor' || key === 'patch') {
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if (v1[key] !== v2[key]) {
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return prefix + key
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}
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}
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}
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return defaultResult // may be undefined
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}
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}
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module.exports = diff
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