这是我的变体，可能比大多数其他变体少regexp：y，但它可以工作：

function getNumbers(str) {
  return `\n${str}`.split('\n## ')
    .map(x => [...x.matchAll(/\{~(\d|\.)*\}/g)].map(x => x[0]))
    .map(x => [x[0], x.slice(-1)]).flat(2).filter(x => x)
    .map(x => +x.replace(/[\{\}~]/g, ''));
}

这是可能的lookarounds，JS支持。
由于我们经常重用原始模式，让我们将其存储在变量中：

const pattern = String.raw`{([^}]*(?:~\d*(?:\.\d+)?)[^}]*)}`;

不包含上述模式的字符串看起来像这样，其中[^]表示“所有字符”，类似于带有s标志的.：

`(?:(?!${pattern})[^])*`

由此，我们构建了我们的lookahead和lookbehind：

// Pattern, anything that doesn't contain pattern, then header or end of string (not end of line).
const lookahead = `${pattern}(?=(?:(?!${pattern})[^])*(?:^##.+|(?![^])))`;

// Header, anything that doesn't contain pattern, then pattern itself.
const lookbehind = `(?<=^##.+$(?:(?!${pattern})[^])*)${pattern}`;

下面是我们的最后步骤：

const regex = new RegExp(`${lookbehind}|${lookahead}`, 'gm');

// Filter out unmatched groups.
[...text.matchAll(regex)].map(match => match.filter(Boolean));

试试看：

console.config({ maximize: true });

function match(string) {
  const pattern = String.raw`{([^}]*(?:~\d*(?:\.\d+)?)[^}]*)}`;
  const lookahead = `${pattern}(?=(?:(?!${pattern})[^])*(?:^##.+|(?![^])))`;
  const lookbehind = `(?<=^##.+$(?:(?!${pattern})[^])*)${pattern}`;
  const regex = new RegExp(`${lookbehind}|${lookahead}`, 'gm');
  
  console.log(regex); // Just to show you how monstrous it is.
  
  return string.matchAll(regex);
}

const text = `
## Header 1

{~1.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~2.0} vitae congue erat accumsan nec. {~3.0}

{~4.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~5.0} vitae congue erat accumsan nec. {~6.0}

{~7.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~8.0} vitae congue erat accumsan nec. {~9.0}

## Header 2

{~10.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~11.0} vitae congue erat accumsan nec. {~12.0}

{~113.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~14.0} vitae congue erat accumsan nec. {~15.0}

{~16.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~17.0} vitae congue erat accumsan nec. {~18.0}

## Header 3

{~19.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~20.0} vitae congue erat accumsan nec. {~21.0}

{~22.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~23.0} vitae congue erat accumsan nec. {~24.0}

{~25.0} Lorem ipsum dolor sit amet. Sed congue diam turpis, {~26.0} vitae congue erat accumsan nec. {~27.0}
`.trim();

console.log([...match(text)].map(match => match.filter(Boolean)));

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