在一串javascript代碼中查找正則表達式文字

Question

我正在用javascript粗略解析javascript代碼。 我就饒了為什么我需要這樣做的細節，但我只想說，我不想集成的代碼庫一大塊，因為它是不需要我的目的，我保持這種非常輕便是非常重要的並且相對簡單。 因此，請不要建議我使用JsLint或類似的東西。 如果答案是超出您可以粘貼到答案中的代碼，則可能超出我想要的范圍。

我的代碼目前能夠很好地檢測引用的節和注釋，然后匹配花括號，方括號和括號（請確保不要被引號和注釋所混淆，或者不要被引號引起來）。 這就是我需要做的所有事情，而且做得很好……除了一個例外：

可以將其與正則表達式文字混淆。 因此，我希望在檢測javascript字符串中的正則表達式文字方面有所幫助，以便我能夠適當地處理它們。

像這樣：

function getRegExpLiterals (stringOfJavascriptCode) {
  var output = [];
  // todo!
  return output;
}

var jsString =  "var regexp1 = /abcd/g, regexp1 = /efg/;"
console.log (getRegExpLiterals (jsString));

// should print:
// [{startIndex: 13, length: 7}, {startIndex: 32, length: 5}]

Answer 1

es5-lexer是一種JS詞法分析器，它使用非常精確的試探法將JS代碼中的正則表達式與除法表達式區分開來，並且還提供了令牌級別的轉換，您可以使用該轉換來確保生成的程序將被相同的方式解釋。與詞法分析器一樣的完整JS解析器。

確定/是否啟動正則表達式的位在guess_is_regexp.js ，並且測試從scanner_test.js第401行開始

var REGEXP_PRECEDER_TOKEN_RE = new RegExp(
  "^(?:"  // Match the whole tokens below
    + "break"
    + "|case"
    + "|continue"
    + "|delete"
    + "|do"
    + "|else"
    + "|finally"
    + "|in"
    + "|instanceof"
    + "|return"
    + "|throw"
    + "|try"
    + "|typeof"
    + "|void"
    // Binary operators which cannot be followed by a division operator.
    + "|[+]"  // Match + but not ++.  += is handled below.
    + "|-"    // Match - but not --.  -= is handled below.
    + "|[.]"    // Match . but not a number with a trailing decimal.
    + "|[/]"  // Match /, but not a regexp.  /= is handled below.
    + "|,"    // Second binary operand cannot start a division.
    + "|[*]"  // Ditto binary operand.
  + ")$"
  // Or match a token that ends with one of the characters below to match
  // a variety of punctuation tokens.
  // Some of the single char tokens could go above, but putting them below
  // allows closure-compiler's regex optimizer to do a better job.
  // The right column explains why the terminal character to the left can only
  // precede a regexp.
  + "|["
    + "!"  // !           prefix operator operand cannot start with a division
    + "%"  // %           second binary operand cannot start with a division
    + "&"  // &, &&       ditto binary operand
    + "("  // (           expression cannot start with a division
    + ":"  // :           property value, labelled statement, and operand of ?:
           //             cannot start with a division
    + ";"  // ;           statement & for condition cannot start with division
    + "<"  // <, <<, <<   ditto binary operand
    // !=, !==, %=, &&=, &=, *=, +=, -=, /=, <<=, <=, =, ==, ===, >=, >>=, >>>=,
    // ^=, |=, ||=
    // All are binary operands (assignment ops or comparisons) whose right
    // operand cannot start with a division operator
    + "="
    + ">"  // >, >>, >>>  ditto binary operand
    + "?"  // ?           expression in ?: cannot start with a division operator
    + "["  // [           first array value & key expression cannot start with
           //             a division
    + "^"  // ^           ditto binary operand
    + "{"  // {           statement in block and object property key cannot start
           //             with a division
    + "|"  // |, ||       ditto binary operand
    + "}"  // }           PROBLEMATIC: could be an object literal divided or
           //             a block.  More likely to be start of a statement after
           //             a block which cannot start with a /.
    + "~"  // ~           ditto binary operand
  + "]$"
  // The exclusion of ++ and -- from the above is also problematic.
  // Both are prefix and postfix operators.
  // Given that there is rarely a good reason to increment a regular expression
  // and good reason to have a post-increment operator as the left operand of
  // a division (x++ / y) this pattern treats ++ and -- as division preceders.
  );