Downgrade to semver compatible with Node v8

lib/rules/no-unsupported-features.js

@@ -129,7 +129,7 @@ module.exports = {
      * @returns {boolean} `true` if it's supporting.
      */
     function isNotSupportingVersion(aCase) {
-      return !semver.subset(versionRange, getSemverRange(aCase.supported))
+      return !semverSubset(versionRange, getSemverRange(aCase.supported))
     }
 
     /** @type {TemplateListener} */
@@ -163,3 +163,208 @@ module.exports = {
     )
   }
 }
+
+// TODO replace semver.subset() in the major version.
+/**
+ * semver.subset()
+ *
+ * We need to use a copy of the semver source code until a major version upgrade.
+ *
+ * @see https://github.com/npm/node-semver/blob/e79ac3a450e8bb504e78b8159e3efc70895699b8/ranges/subset.js#L43
+ * @license ISC at Isaac Z. Schlueter and Contributors
+ * https://github.com/npm/node-semver/blob/master/LICENSE
+ *
+ * @param {semver.Range} sub
+ * @param {semver.Range} dom
+ */
+function semverSubset(sub, dom) {
+  if (sub === dom) return true
+
+  sub = new semver.Range(sub)
+  dom = new semver.Range(dom)
+  let sawNonNull = false
+
+  // eslint-disable-next-line no-labels
+  OUTER: for (const simpleSub of sub.set) {
+    for (const simpleDom of dom.set) {
+      const isSub = simpleSubset(simpleSub, simpleDom)
+      sawNonNull = sawNonNull || isSub !== null
+      // eslint-disable-next-line no-labels
+      if (isSub) continue OUTER
+    }
+    if (sawNonNull) return false
+  }
+  return true
+}
+
+/**
+ * @license ISC at Isaac Z. Schlueter and Contributors
+ * https://github.com/npm/node-semver/blob/master/LICENSE
+ * @param {readonly semver.Comparator[]} sub
+ * @param {readonly semver.Comparator[]} dom
+ */
+function simpleSubset(sub, dom) {
+  if (sub === dom) return true
+
+  /**
+   * @param {semver.Comparator} c
+   */
+  function isAny(c) {
+    return Object.keys(c.semver).length === 0
+  }
+
+  if (sub.length === 1 && isAny(sub[0])) {
+    if (dom.length === 1 && isAny(dom[0])) return true
+    else sub = [new semver.Comparator('>=0.0.0')]
+  }
+
+  if (dom.length === 1 && isAny(dom[0])) {
+    dom = [new semver.Comparator('>=0.0.0')]
+  }
+
+  const eqSet = new Set()
+  let gt, lt
+  for (const c of sub) {
+    if (c.operator === '>' || c.operator === '>=') gt = higherGT(gt, c)
+    else if (c.operator === '<' || c.operator === '<=') lt = lowerLT(lt, c)
+    else eqSet.add(c.semver)
+  }
+
+  if (eqSet.size > 1) return null
+
+  let gtltComp
+  if (gt && lt) {
+    gtltComp = semver.compare(gt.semver, lt.semver)
+    if (gtltComp > 0) return null
+    else if (gtltComp === 0 && (gt.operator !== '>=' || lt.operator !== '<='))
+      return null
+  }
+
+  // will iterate one or zero times
+  for (const eq of eqSet) {
+    if (gt && !semver.satisfies(eq, String(gt))) return null
+
+    if (lt && !semver.satisfies(eq, String(lt))) return null
+
+    for (const c of dom) {
+      if (!semver.satisfies(eq, String(c))) return false
+    }
+
+    return true
+  }
+
+  let higher, lower
+  let hasDomLT, hasDomGT
+  // if the subset has a prerelease, we need a comparator in the superset
+  // with the same tuple and a prerelease, or it's not a subset
+  let needDomLTPre = lt && lt.semver.prerelease.length ? lt.semver : false
+  let needDomGTPre = gt && gt.semver.prerelease.length ? gt.semver : false
+  // exception: <1.2.3-0 is the same as <1.2.3
+  if (
+    needDomLTPre &&
+    needDomLTPre.prerelease.length === 1 &&
+    lt &&
+    lt.operator === '<' &&
+    needDomLTPre.prerelease[0] === 0
+  ) {
+    needDomLTPre = false
+  }
+
+  for (const c of dom) {
+    hasDomGT = hasDomGT || c.operator === '>' || c.operator === '>='
+    hasDomLT = hasDomLT || c.operator === '<' || c.operator === '<='
+    if (gt) {
+      if (needDomGTPre) {
+        if (
+          c.semver.prerelease &&
+          c.semver.prerelease.length &&
+          c.semver.major === needDomGTPre.major &&
+          c.semver.minor === needDomGTPre.minor &&
+          c.semver.patch === needDomGTPre.patch
+        ) {
+          needDomGTPre = false
+        }
+      }
+      if (c.operator === '>' || c.operator === '>=') {
+        higher = higherGT(gt, c)
+        if (higher === c && higher !== gt) return false
+      } else if (
+        gt.operator === '>=' &&
+        !semver.satisfies(gt.semver, String(c))
+      )
+        return false
+    }
+    if (lt) {
+      if (needDomLTPre) {
+        if (
+          c.semver.prerelease &&
+          c.semver.prerelease.length &&
+          c.semver.major === needDomLTPre.major &&
+          c.semver.minor === needDomLTPre.minor &&
+          c.semver.patch === needDomLTPre.patch
+        ) {
+          needDomLTPre = false
+        }
+      }
+      if (c.operator === '<' || c.operator === '<=') {
+        lower = lowerLT(lt, c)
+        if (lower === c && lower !== lt) return false
+      } else if (
+        lt.operator === '<=' &&
+        !semver.satisfies(lt.semver, String(c))
+      )
+        return false
+    }
+    if (!c.operator && (lt || gt) && gtltComp !== 0) return false
+  }
+
+  // if there was a < or >, and nothing in the dom, then must be false
+  // UNLESS it was limited by another range in the other direction.
+  // Eg, >1.0.0 <1.0.1 is still a subset of <2.0.0
+  if (gt && hasDomLT && !lt && gtltComp !== 0) return false
+
+  if (lt && hasDomGT && !gt && gtltComp !== 0) return false
+
+  // we needed a prerelease range in a specific tuple, but didn't get one
+  // then this isn't a subset.  eg >=1.2.3-pre is not a subset of >=1.0.0,
+  // because it includes prereleases in the 1.2.3 tuple
+  if (needDomGTPre || needDomLTPre) return false
+
+  return true
+}
+
+/**
+ * @license ISC at Isaac Z. Schlueter and Contributors
+ * https://github.com/npm/node-semver/blob/master/LICENSE
+ * @param {semver.Comparator | void} a
+ * @param {semver.Comparator} b
+ */
+const higherGT = (a, b) => {
+  if (!a) return b
+  const comp = semver.compare(a.semver, b.semver)
+  return comp > 0
+    ? a
+    : comp < 0
+    ? b
+    : b.operator === '>' && a.operator === '>='
+    ? b
+    : a
+}
+
+/**
+ * @license ISC at Isaac Z. Schlueter and Contributors
+ * https://github.com/npm/node-semver/blob/master/LICENSE
+ * @param {semver.Comparator | void} a
+ * @param {semver.Comparator} b
+ */
+const lowerLT = (a, b) => {
+  if (!a) return b
+  const comp = semver.compare(a.semver, b.semver)
+  return comp < 0
+    ? a
+    : comp > 0
+    ? b
+    : b.operator === '<' && a.operator === '<='
+    ? b
+    : a
+}

package.json

@@ -55,7 +55,7 @@
   "dependencies": {
     "eslint-utils": "^2.1.0",
     "natural-compare": "^1.4.0",
-    "semver": "^7.3.2",
+    "semver": "^6.3.0",
     "vue-eslint-parser": "^7.8.0"
   },
   "devDependencies": {