lib: document more internal helpers

Signed-off-by: Filip Skokan <[email protected]>

Author: panva

lib/internal/crypto/keys.js

@@ -944,14 +944,31 @@ function getCryptoKeyAlgorithm(key) {
   return getSlots(key)[kSlotAlgorithm];
 }
 
+/**
+ * Returns the CryptoKey's native `[[usages]]` mask.
+ * @param {CryptoKey} key
+ * @returns {number}
+ */
 function getCryptoKeyUsagesMask(key) {
   return getSlots(key)[kSlotUsagesMask];
 }
 
+/**
+ * Returns whether a CryptoKey's `[[usages]]` contains `usage`.
+ * @param {CryptoKey} key
+ * @param {string} usage
+ * @returns {boolean}
+ */
 function hasCryptoKeyUsage(key, usage) {
   return hasUsage(getCryptoKeyUsagesMask(key), usage);
 }
 
+/**
+ * Returns the CryptoKey's cached canonical usages array for internal
+ * consumers, expanding it from the native usage mask on first access.
+ * @param {Array} slots
+ * @returns {string[]}
+ */
 function getCryptoKeyUsagesFromSlots(slots) {
   let usages = slots[kSlotUsages];
   if (usages === undefined) {
@@ -963,7 +980,8 @@ function getCryptoKeyUsagesFromSlots(slots) {
 
 /**
  * Returns the CryptoKey's `[[usages]]` internal slot, bypassing the
- * public `usages` getter (which returns a cloned array).
+ * public `usages` getter (which returns a cloned array). The internal
+ * array is expanded lazily from the native usage mask.
  * @param {CryptoKey} key
  * @returns {string[]}
  */

lib/internal/crypto/util.js

@@ -717,6 +717,12 @@ function getStringOption(options, key) {
   return value;
 }
 
+/**
+ * Returns the requested usages that are present in `usageSet`.
+ * @param {SafeSet<string>} usageSet
+ * @param {...string} usages
+ * @returns {SafeSet<string>}
+ */
 function getUsagesUnion(usageSet, ...usages) {
   const newset = new SafeSet();
   for (let n = 0; n < usages.length; n++) {
@@ -768,6 +774,12 @@ function getUsagesMask(usageSet) {
   return mask;
 }
 
+/**
+ * Returns whether `mask` contains `usage`.
+ * @param {number} mask
+ * @param {string} usage
+ * @returns {boolean}
+ */
 function hasUsage(mask, usage) {
   return (mask & kUsageMasks[usage]) !== 0;
 }