diff --git a/src/encode.js b/src/encode.js
index aef0c61..17c4f4e 100644
--- a/src/encode.js
+++ b/src/encode.js
@@ -4,29 +4,30 @@ const { isObject } = require('./objects')
 const { isNonEmptyString } = require('./strings')
 
 const reusedSearchParams = new URLSearchParams()
+const reusedSearchParamKey = '_'
+const reusedSearchParamOffset = 2 // '_='.length
 
 const { encodeURIComponent } = globalThis
 
-function encodeWithColonAndForwardSlash(str) {
-    return encodeURIComponent(str).replace(/%3A/g, ':').replace(/%2F/g, '/')
-}
-
-function encodeWithColonAndPlusSign(str) {
-    return encodeURIComponent(str).replace(/%3A/g, ':').replace(/%2B/g, '+')
-}
-
-function encodeWithForwardSlash(str) {
-    return encodeURIComponent(str).replace(/%2F/g, '/')
-}
-
 function encodeNamespace(namespace) {
     return isNonEmptyString(namespace)
-        ? encodeWithColonAndForwardSlash(namespace)
+        ? encodeURIComponent(namespace)
+              .replace(/%3A/g, ':')
+              .replace(/%2F/g, '/')
         : ''
 }
 
-function encodeVersion(version) {
-    return isNonEmptyString(version) ? encodeWithColonAndPlusSign(version) : ''
+function encodeQualifierParam(param) {
+    if (isNonEmptyString(param)) {
+        // Param key and value are encoded with `percentEncodeSet` of
+        // 'application/x-www-form-urlencoded' and `spaceAsPlus` of `true`.
+        // https://url.spec.whatwg.org/#urlencoded-serializing
+        reusedSearchParams.set(reusedSearchParamKey, param)
+        return replacePlusSignWithPercentEncodedSpace(
+            reusedSearchParams.toString().slice(reusedSearchParamOffset)
+        )
+    }
+    return ''
 }
 
 function encodeQualifiers(qualifiers) {
@@ -43,26 +44,16 @@ function encodeQualifiers(qualifiers) {
     return ''
 }
 
-function encodeQualifierParam(qualifierValue) {
-    return isNonEmptyString
-        ? encodeURLSearchParamWithPercentEncodedSpace(param)
-        : ''
-}
-
 function encodeSubpath(subpath) {
-    return isNonEmptyString(subpath) ? encodeWithForwardSlash(subpath) : ''
-}
-
-function encodeURLSearchParam(param) {
-    // Param key and value are encoded with `percentEncodeSet` of
-    // 'application/x-www-form-urlencoded' and `spaceAsPlus` of `true`.
-    // https://url.spec.whatwg.org/#urlencoded-serializing
-    reusedSearchParams.set('_', qualifierValue)
-    return reusedSearchParams.toString().slice(2)
+    return isNonEmptyString(subpath)
+        ? encodeURIComponent(subpath).replace(/%2F/g, '/')
+        : ''
 }
 
-function encodeURLSearchParamWithPercentEncodedSpace(str) {
-    return replacePlusSignWithPercentEncodedSpace(encodeURLSearchParam(str))
+function encodeVersion(version) {
+    return isNonEmptyString(version)
+        ? encodeURIComponent(version).replace(/%3A/g, ':').replace(/%2B/g, '+')
+        : ''
 }
 
 function replacePlusSignWithPercentEncodedSpace(str) {
@@ -71,15 +62,10 @@ function replacePlusSignWithPercentEncodedSpace(str) {
 }
 
 module.exports = {
-    encodeWithColonAndForwardSlash,
-    encodeWithColonAndPlusSign,
-    encodeWithForwardSlash,
     encodeNamespace,
     encodeVersion,
     encodeQualifiers,
     encodeQualifierParam,
     encodeSubpath,
-    encodeURIComponent,
-    encodeURLSearchParam,
-    encodeURLSearchParamWithPercentEncodedSpace
+    encodeURIComponent
 }
diff --git a/src/purl-component.js b/src/purl-component.js
index e61dffd..db76f15 100644
--- a/src/purl-component.js
+++ b/src/purl-component.js
@@ -12,28 +12,28 @@ const {
 const { createHelpersNamespaceObject } = require('./helpers')
 
 const {
-    normalizeName,
+    normalizeType,
     normalizeNamespace,
+    normalizeName,
+    normalizeVersion,
     normalizeQualifiers,
-    normalizeSubpath,
-    normalizeType,
-    normalizeVersion
+    normalizeSubpath
 } = require('./normalize')
 
-const { localeCompare } = require('./strings')
+const { localeCompare, isNonEmptyString } = require('./strings')
 
 const {
-    validateName,
+    validateType,
     validateNamespace,
+    validateName,
+    validateVersion,
     validateQualifiers,
     validateQualifierKey,
-    validateSubpath,
-    validateType,
-    validateVersion
+    validateSubpath
 } = require('./validate')
 
 const PurlComponentEncoder = (comp) =>
-    typeof comp === 'string' && comp.length ? encodeURIComponent(comp) : ''
+    isNonEmptyString(comp) ? encodeURIComponent(comp) : ''
 
 const PurlComponentStringNormalizer = (comp) =>
     typeof comp === 'string' ? comp : undefined
diff --git a/src/validate.js b/src/validate.js
index 42a41cc..70dff28 100644
--- a/src/validate.js
+++ b/src/validate.js
@@ -1,6 +1,7 @@
 'use strict'
 
 const { isNullishOrEmptyString } = require('./lang')
+const { isNonEmptyString } = require('./strings')
 
 function validateEmptyByType(type, name, value, throws) {
     if (!isNullishOrEmptyString(value)) {
@@ -104,7 +105,7 @@ function validateRequiredByType(type, name, value, throws) {
 }
 
 function validateStartsWithoutNumber(name, value, throws) {
-    if (value.length !== 0) {
+    if (isNonEmptyString(value)) {
         const code = value.charCodeAt(0)
         if (code >= 48 /*'0'*/ && code <= 57 /*'9'*/) {
             if (throws) {