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chore: support keepStale in set method
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@wellwelwel
wellwelwel committed Sep 20, 2024
1 parent 29afa2d commit e76d40b
Showing 1 changed file with 31 additions and 18 deletions.
49 changes: 31 additions & 18 deletions src/index.ts
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Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
type Binary = 0 | 1;

export type CacheOptions<Key = unknown, Value = unknown> = {
/** Maximum number of items the cache can hold. */
max: number;
Expand All @@ -8,7 +10,7 @@ export type CacheOptions<Key = unknown, Value = unknown> = {
*/
staleAt?: number;
/**
* When `true` and `staleAt` is set, items remain staleAt based on their initial expiration.
* When `true` and `staleAt` is set, items remain stale based on their initial expiration.
*
* @default undefined
*/
Expand All @@ -27,10 +29,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
if (!(Number.isInteger(max) && max > 0))
throw new TypeError('`max` must be a positive integer');

if (
(typeof staleAt !== 'undefined' && typeof staleAt !== 'number') ||
(typeof staleAt === 'number' && staleAt <= 0)
)
if (staleAt !== undefined && (typeof staleAt !== 'number' || staleAt <= 0))
throw new TypeError('`staleAt` must be a positive number');

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const Age = (() => {
Expand All @@ -51,6 +50,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
const valList: (Value | undefined)[] = new Array(max).fill(undefined);
const expList: number[] = new Array(max).fill(0);
const ageList: number[] = new Array(max).fill(0);
const staleList: Binary[] = new Array(max).fill(0);
const next: number[] = new Array(max).fill(0);
const prev: number[] = new Array(max).fill(0);

Expand Down Expand Up @@ -82,6 +82,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
valList[evictHead] = undefined;
expList[evictHead] = 0;
ageList[evictHead] = 0;
staleList[evictHead] = 0;
head = next[evictHead];

if (head !== 0) prev[head] = 0;
Expand All @@ -108,6 +109,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
valList[index] = undefined;
expList[index] = 0;
ageList[index] = 0;
staleList[index] = 0;

const prevIndex = prev[index];
const nextIndex = next[index];
Expand Down Expand Up @@ -163,13 +165,18 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
maxAge: ageItem,
staleAt: timeRemaining > 0 ? timeRemaining : 0,
isStale,
keepStale: Boolean(staleList[index]),
position,
};
};

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return {
/** Adds a key-value pair to the cache. Updates the value if the key already exists. */
set(key: Key, value: Value, options?: { staleAt?: number }): undefined {
set(
key: Key,
value: Value,
options?: { staleAt?: number; keepStale?: boolean }
): undefined {
if (key === undefined) return;

let index = keyMap.get(key);
Expand All @@ -187,10 +194,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
options?.staleAt !== undefined ? options.staleAt : staleAt;

if (keyMaxAge !== undefined) {
if (
(typeof staleAt !== 'undefined' && typeof staleAt !== 'number') ||
(typeof staleAt === 'number' && staleAt <= 0)
)
if (typeof keyMaxAge !== 'number' || keyMaxAge <= 0)
throw new TypeError('`staleAt` must be a positive number');

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expList[index] = Age.now() + keyMaxAge;
Expand All @@ -200,6 +204,11 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
ageList[index] = 0;
}

staleList[index] =
options?.keepStale !== undefined
? (Number(options.keepStale) as Binary)
: (Number(keepStale === true) as Binary);

if (size === 1) head = tail = index;
else setTail(index, 'set');
},
Expand All @@ -213,12 +222,10 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {

if (index !== tail) setTail(index, 'get');

if (keepStale !== true) {
if (staleList[index] === 0) {
const itemMaxAge = ageList[index];

if (itemMaxAge !== 0) {
expList[index] = Age.now() + itemMaxAge;
}
if (itemMaxAge !== 0) expList[index] = Age.now() + itemMaxAge;
}

return valList[index];
Expand All @@ -239,12 +246,10 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
if (index === undefined) return false;
if (!_checkAge(key)) return false;

if (keepStale !== true) {
if (staleList[index] === 0) {
const itemMaxAge = ageList[index];

if (itemMaxAge !== 0) {
expList[index] = Age.now() + itemMaxAge;
}
if (itemMaxAge !== 0) expList[index] = Age.now() + itemMaxAge;
}

return true;
Expand Down Expand Up @@ -293,6 +298,8 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
staleAt: number;

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/** When `true`, the next interaction with the key will evict it. */
isStale: boolean;

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/** Whether the item keeps its stale time upon access. */
keepStale: boolean;

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/** From the most recent (`0`) to the oldest (`max`). */
position: number;
}
Expand Down Expand Up @@ -359,6 +366,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
valList.fill(undefined);
expList.fill(0);
ageList.fill(0);
staleList.fill(0);

free = [];
size = 0;
Expand All @@ -385,6 +393,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
);
const newExpList: number[] = new Array(newMax).fill(0);
const newAgeList: number[] = new Array(newMax).fill(0);
const newStaleList: Binary[] = new Array(newMax).fill(0);
const newNext: number[] = new Array(newMax).fill(0);
const newPrev: number[] = new Array(newMax).fill(0);

Expand All @@ -396,6 +405,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
newValList[i] = valList[current];
newExpList[i] = expList[current];
newAgeList[i] = ageList[current];
newStaleList[i] = staleList[current];
newNext[i] = i + 1;
newPrev[i] = i - 1;
keyMap.set(newKeyList[i]!, i);
Expand All @@ -410,6 +420,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
valList.length = newMax;
expList.length = newMax;
ageList.length = newMax;
staleList.length = newMax;
next.length = newMax;
prev.length = newMax;

Expand All @@ -418,6 +429,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
valList[i] = newValList[i];
expList[i] = newExpList[i];
ageList[i] = newAgeList[i];
staleList[i] = newStaleList[i];
next[i] = newNext[i];
prev[i] = newPrev[i];
}
Expand All @@ -432,6 +444,7 @@ export const createLRU = <Key, Value>(options: CacheOptions<Key, Value>) => {
valList.push(...new Array(fill).fill(undefined));
expList.push(...new Array(fill).fill(0));
ageList.push(...new Array(fill).fill(0));
staleList.push(...new Array(fill).fill(0));
next.push(...new Array(fill).fill(0));
prev.push(...new Array(fill).fill(0));
}
Expand Down

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