getHashCode.js

/**
 * 获取字符串的哈希值
 * @param {String} str
 * @param {Boolean} caseSensitive
 * @return {Number} hashCode
 */
getHashCode:function(str,caseSensitive){
    if(!caseSensitive){
        str = str.toLowerCase();
    }
    // 1315423911=b'1001110011001111100011010100111'
    var hash  =   1315423911,i,ch;
    for (i = str.length - 1; i >= 0; i--) {
        ch = str.charCodeAt(i);
        hash ^= ((hash << 5) + ch + (hash >> 2));
    }

    return  (hash & 0x7FFFFFFF);
}


/**
 * JS中实现JAVA的hashCode算法
 * @param {String} str
 * @return {Number} hashCode
 */

function hashCode(str){
        var h = 0, off = 0;
        var len = str.length;
        for(var i = 0; i < len; i++){
            h = 31 * h + str.charCodeAt(off++);
        }
    var t=-2147483648*2;
    while(h>2147483647){
      h+=t
    }
        return h;
}

/**
 * String hash code
 * @param {String} str
 * @return {int}
 */
function hashCode(str) {
  for (var result = 0, i = 0; i < str.length; i++) {
		result = (result << 5) - result + str.charCodeAt(i);
		result &= result;
	}
	return result;
}
// Compressed
function(e){for(var r=0,i=0;i<e.length;i++)r=(r<<5)-r+e.charCodeAt(i),r&=r;return r};
// Usage
console.log(hashCode("Secret message"));