Function tryParseInt

internal/jsnum/string.go:120–171

(s string)

var errUnknownPrefix = errors.New("unknown number prefix")

func tryParseInt(s string) (Number, bool) {
	var i int64
	var err error
	var hasIntResult bool

	if len(s) > 2 {
		prefix, rest := s[:2], s[2:]
		switch prefix {
		case "0b", "0B":
			if !isAllBinaryDigits(rest) {
				return NaN(), true
			}
			i, err = strconv.ParseInt(rest, 2, 64)
			hasIntResult = true
		case "0o", "0O":
			if !isAllOctalDigits(rest) {
				return NaN(), true
			}
			i, err = strconv.ParseInt(rest, 8, 64)
			hasIntResult = true
		case "0x", "0X":
			if !isAllHexDigits(rest) {
				return NaN(), true
			}
			i, err = strconv.ParseInt(rest, 16, 64)
			hasIntResult = true
		}
	}

	if !hasIntResult {
		// StringToNumber does not parse leading zeros as octal.
		s = trimLeadingZeros(s)
		if !isAllDigits(s) {
			return 0, false
		}
		i, err = strconv.ParseInt(s, 10, 64)
		hasIntResult = true
	}

	if hasIntResult && err == nil {
		return Number(i), true
	}

	// Using this to parse large integers.
	bi, ok := new(big.Int).SetString(s, 0)
	if !ok {
		return NaN(), true
	}

	f, _ := bi.Float64()
	return Number(f), true
}

func parseFloatString(s string) float64 {
	var hasDot, hasExp bool