Vue中的cached

源码：

/**
 * Create a cached version of a pure function.
 */
function cached (fn) {
  var cache = Object.create(null);
  return (function cachedFn (str) {
    var hit = cache[str];
    return hit || (cache[str] = fn(str))
  })
}

应用：

/**
 * Camelize a hyphen-delimited string.
 */
var camelizeRE = /-(\w)/g;
var camelize = cached(function (str) {
  return str.replace(camelizeRE, function (_, c) { return c ? c.toUpperCase() : ''; })
});

/**
* Hyphenate a camelCase string.
*/
var hyphenateRE = /\B([A-Z])/g;
var hyphenate = cached(function (str) {
    return str.replace(hyphenateRE, '-$1').toLowerCase()
});

测试

camelize('test-case');  //"testCase"

hyphenate('testCase'); //"test-case"

知识点

1.闭包

2.String.prototype.replace

3.正则\b 和 \B

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