@antv/util/esm/lodash/memoize.js

> AntV 底层依赖的工具库，不建议在自己业务中使用。

function flru(max) {
    var num, curr, prev;
    var limit = max || 1;
    function keep(key, value) {
        if (++num > limit) {
            prev = curr;
            reset(1);
            ++num;
        }
        curr[key] = value;
    }
    function reset(isPartial) {
        num = 0;
        curr = Object.create(null);
        isPartial || (prev = Object.create(null));
    }
    reset();
    return {
        clear: reset,
        has: function (key) {
            return curr[key] !== void 0 || prev[key] !== void 0;
        },
        get: function (key) {
            var val = curr[key];
            if (val !== void 0)
                return val;
            if ((val = prev[key]) !== void 0) {
                keep(key, val);
                return val;
            }
        },
        set: function (key, value) {
            if (curr[key] !== void 0) {
                curr[key] = value;
            }
            else {
                keep(key, value);
            }
        },
    };
}
var CacheMap = new Map();
/**
 * 缓存函数的计算结果，避免重复计算
 * @example
 * _.memoize(calColor);
 * _.memoize(calColor, (...args) => args[0]);
 * @param fn 缓存的函数
 * @param resolver 生成缓存 key 的函数
 * @param maxSize lru 缓存的大小
 */
export default function memoize(fn, resolver, maxSize) {
    if (maxSize === void 0) { maxSize = 128; }
    var memoized = function () {
        var args = [];
        for (var _i = 0; _i < arguments.length; _i++) {
            args[_i] = arguments[_i];
        }
        // 使用方法构造 key，如果不存在 resolver，则直接取第一个参数作为 key
        var key = resolver ? resolver.apply(this, args) : args[0];
        if (!CacheMap.has(fn))
            CacheMap.set(fn, flru(maxSize));
        var cache = CacheMap.get(fn);
        if (cache.has(key))
            return cache.get(key);
        var result = fn.apply(this, args);
        cache.set(key, result);
        return result;
    };
    return memoized;
}
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