在JavaScript中模拟类SQL

只要您首先对模式中的正则表达式字符进行转义,您所拥有的将起作用。下面是一个例子 Simon Willison’s blog :

RegExp.escape = function(text) {
  if (!arguments.callee.sRE) {
    var specials = [
      '/', '.', '*', '+', '?', '|',
      '(', ')', '[', ']', '{', '}', '\\'
    ];
    arguments.callee.sRE = new RegExp(
      '(\\' + specials.join('|\\') + ')', 'g'
    );
  }
  return text.replace(arguments.callee.sRE, '\\$1');
}

likeExpr = RegExp.escape(likeExpr);
var match = new RegEx(likeExpr.replace("%", ".*").replace("_", ".")).exec(str) != null;

我一直在寻找同一个问题的答案,在阅读Kip的回复后,我得出了以下结论:

String.prototype.like = function(search) {
    if (typeof search !== 'string' || this === null) {return false; }
    // Remove special chars
    search = search.replace(new RegExp("([\\.\\\\\\+\\*\\?\\[\\^\\]\\$\\(\\)\\{\\}\\=\\!\\<\\>\\|\\:\\-])", "g"), "\\$1");
    // Replace % and _ with equivalent regex
    search = search.replace(/%/g, '.*').replace(/_/g, '.');
    // Check matches
    return RegExp('^' + search + '$', 'gi').test(this);
}

然后可以按如下方式使用它(请注意,它忽略大写/小写):

var url = 'http://www.mydomain.com/page1.aspx';
console.log(url.like('%mydomain.com/page_.asp%')); // true

注29/11/2013: 更新为 RegExp.test() 根据下面的Lucios评论改进性能。

这是我使用的一个函数,基于 PHP's preg_quote function :

function regex_quote(str) {
  return str.replace(new RegExp("([\\.\\\\\\+\\*\\?\\[\\^\\]\\$\\(\\)\\{\\}\\=\\!\\<\\>\\|\\:\\-])", "g"), "\\$1");
}

var match = new RegEx(regex_quote(likeExpr).replace("%", ".*").replace("_", ".")).exec(str) != null;

这是一个老问题,但实际上这里没有好的答案。类TSQL表达式可以包含方括号转义部分,这些转义部分已经几乎是有效的正则表达式,并允许匹配 % 和 _ . 例如。:

'75%' LIKE '75[%]'
'[foo]' LIKE '[[]foo]' -- ugh

下面是我将LIKE表达式转换为RegExp的函数。输入分为方括号和非方括号部分。方括号部分只需要反斜杠转义,而非方括号部分在 % _

const likeRegExp = (expression, caseSensitive = false) =>
    new RegExp(`^${
        expression.split(/(\[.+?\])/g)
        .map((s, i) => i % 2 ?
            s.replace(/\\/g, '\\\\') :
            s.replace(/[-\/\\^$*+?.()|[\]{}%_]/g, m => {
                switch(m) {
                    case '%': return '.*';
                    case '_': return '.';
                    default: return `\\${m}`;
                }
            })
        ).join('')
    }$`, caseSensitive ? '' : 'i');

如果要使用正则表达式,可以将字符串的每个字符都用方括号括起来。那么您只有几个字符可以转义。

但更好的选择可能是截断目标字符串,以便长度与搜索字符串匹配,并检查是否相等。

在Chris Van Opstal的回答中,您应该使用replaceAll而不是replace来替换“%”和“"的所有发生。 参考如何进行全部替换- here

Johnny最近来过这里,但这对我很有用。我将其用于spa页面,以避免某些页面在默认页面后显示结果:

function like(haystack,needle){
    needle = needle.split(','); 
    var str = haystack.toLowerCase();
    var n = -1;
    for(var i=0;i<needle.length;i++){
        n = str.search(needle[i]);
        if(n > -1){
            return n;
        }
    }
return n;
}

用法是-此处我不想在工具、联系人或主页上显示任何结果-results()是我在此处不显示的函数:

var n = like($data,'tools,contact,home');
//~ alert(n);
if(n < 0){// does not match anything in the above string
  results($data);
}

我想要的东西,也处理转义通配符 % _ 使用 \% 和 \_ .

以下是我使用反向查找的解决方案:

// escapes RegExp special characters
const escapePattern = s => s.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&');

// converts ILIKE pattern to a RegExp object
const ilikeToRegExp = pattern =>
  new RegExp(
    `^${escapePattern(pattern)}$`
      // convert ILIKE wildcards, don't match escaped
      .replace(/(?<![\\])%/g, '.*')
      .replace(/(?<![\\])_/g, '.')
      // replace ILIKE escapes
      .replace(/\\%/g, '%')
      .replace(/\\_/g, '_'),
    'i'
  );

用法:

ilikeToRegExp('%eLlo WoR%').test('hello world')  
// true

ilikeToRegExp('ello wor').test('hello world')  
// false

ilikeToRegExp('%90\%%').test('...90%...') 
// true

我需要这个,在Safari中逃跑和工作(没有负面表情)。以下是我的想法:

/**
 * Quotes a string following the same rules as https://www.php.net/manual/function.preg-quote.php
 *
 * Sourced from https://locutus.io/php/preg_quote/
 *
 * @param {string} str String to quote.
 * @param {?string} [delimiter] Delimiter to also quote.
 * @returns {string} The quoted string.
 */
function regexQuote(str, delimiter) {
    return (str + '').replace(new RegExp('[.\\\\+*?\\[\\^\\]$(){}=!<>|:\\' + (delimiter || '') + '-]', 'g'), '\\$&');
}

/**
 * Removes the diacritical marks from a string.
 *
 * Diacritical marks: {@link https://unicode-table.com/blocks/combining-diacritical-marks/}
 *
 * @param {string} str The string from which to strip the diacritical marks.
 * @returns {string} Stripped string.
 */
function stripDiacriticalMarks(str) {
    return unorm.nfkd(str).replaceAll(/[\u0300-\u036f]+/g, '');
}

/**
 * Checks if the string `haystack` is like `needle`, `needle` can contain '%' and '_'
 * characters which will behave as if used in a SQL LIKE condition. Character escaping
 * is supported with '\'.
 *
 * @param {string} haystack The string to check if it is like `needle`.
 * @param {string} needle The string used to check if `haystack` is like it.
 * @param {boolean} [ai] Whether to check likeness in an accent-insensitive manner.
 * @param {boolean} [ci] Whether to check likeness in a case-insensitive manner.
 * @returns {boolean} True if `haystack` is like `needle`, otherwise, false.
 */
function strLike(haystack, needle, ai = true, ci = true) {
    if (ai) {
        haystack = stripDiacriticalMarks(haystack);
        needle = stripDiacriticalMarks(needle);
    }

    needle = regexQuote(needle, '/');

    let tokens = [];

    for (let i = 0; i < needle.length; ) {
        if (needle[i] === '\\') {
            i += 2;
            if (i < needle.length) {
                if (needle[i] === '\\') {
                    tokens.push('\\\\');
                    i += 2;
                } else {
                    tokens.push(needle[i]);
                    ++i;
                }
            } else {
                tokens.push('\\\\');
            }
        } else {
            switch (needle[i]) {
                case '_':
                    tokens.push('.')
                    break;
                case '%':
                    tokens.push('.*')
                    break;
                default:
                    tokens.push(needle[i]);
                    break;
            }
            ++i;
        }
    }

    return new RegExp(`^${tokens.join('')}$`, `u${ci ? 'i' : ''}`).test(haystack);
}

/**
 * Escapes a string in a way that `strLike` will match it as-is, thus '%' and '_'
 * would match a literal '%' and '_' respectively (and not behave as in a SQL LIKE
 * condition).
 *
 * @param {string} str The string to escape.
 * @returns {string} The escaped string.
 */
function escapeStrLike(str) {
    let tokens = [];

    for (let i = 0; i < str.length; i++) {
        switch (str[i]) {
            case '\\':
                tokens.push('\\\\');
                break;
            case '%':
                tokens.push('\\%')
                break;
            case '_':
                tokens.push('\\_')
                break;
            default:
                tokens.push(str[i]);
        }
    }

    return tokens.join('');
}

unorm

strLike('Hello 🙃', 'Hello _'); // true
strLike('Hello 🙃', '_e%o__');  // true
strLike('asdfas \\🙃H\\\\%🙃É\\l\\_🙃\\l\\o asdfasf', '%' . escapeStrLike('\\🙃h\\\\%🙃e\\l\\_🙃\\l\\o') . '%'); // true

最后,我根据这里的一些答案编写了一个函数,对我来说效果很好。我需要保留“startswith%”和“%endswith”语法,并且不返回与空搜索字符串匹配的内容。

function sqlLIKE(target, likeExp) {
  let regex = likeExp
    .replaceAll(/([.*+?^=!:${}()|[\]\/\\])/g, '\\$1')
    .replaceAll("%", ".*")
    .replaceAll("_", ".");

  if (likeExp.charAt(0) !== '%' || !likeExp.includes('%')) regex = `^${regex}`;

  if (likeExp.charAt(likeExp.length - 1) !== '%' || !likeExp.includes('%')) regex = `${regex}$`;

  return new RegExp(regex).exec(target) !== null;
}