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fifoStrategy.js
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fifoStrategy.js
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const { CacheConfig } = require("../config/cacheConfigs");
class FifoStrategy {
_byteSize = 0;
_data = {};
_keyStack = [];
constructor() {
}
get(key) {
return this._data[key];
}
set(key, value) {
this.validateSize(key, value, this._byteSize);
this._data[key] = value;
this._keyStack.push(key);
this._byteSize += this.getByteSize(key) + this.getByteSize(value);
}
getByteSize(str) {
try {
const bytes = Buffer.byteLength(str, "ascii");
return bytes;
} catch (error) {
return 0;
}
};
validateSize(key, value) {
const keyValSize = this.getByteSize(key) + this.getByteSize(value);
while (this._byteSize + keyValSize > CacheConfig.MAXIMUM_BYTES_SIZE) {
this.removeItem();
}
}
removeItem() {
const removeKey = this._keyStack.shift();
const removeVal = this._data[removeKey];
delete this._data[removeKey];
this._byteSize -= this.getByteSize(removeKey) + this.getByteSize(removeVal);
}
}
module.exports = {
FifoStrategy,
}