> For the complete documentation index, see [llms.txt](https://gu-xionghong.gitbook.io/lodash-analysis/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gu-xionghong.gitbook.io/lodash-analysis/.internal/basetonumber.md).

# baseToNumber

> Overthinking ruins you. Ruins the situation, twists it around, makes you worry and just makes everything much worse than it actually is. — Unknown

本文为 《lodash 源码阅读》 系列文章，后续内容会在 [github](https://github.com/gu-xionghong/lodash-analysis) 中发布，欢迎 star，[gitbook](https://gu-xionghong.gitbook.io/lodash-analysis/) 同步更新。

## 依赖

```javascript
import isSymbol from '../isSymbol.js';
```

* [lodash 源码阅读 —— isSymbol](/lodash-analysis/lang/issymbol.md)

## 源码

```javascript
/** 声明 NAN 变量 */
const NAN = 0 / 0;

/**
 * `toNumber`的基本实现，它不能确保正确转换二进制，十六进制或八进制字符串值。
 *
 * @private
 * @param {*} value 需要处理的值
 * @returns {number} 返回一个数值
 */
function baseToNumber(value) {
  if (typeof value == 'number') {
    return value;
  }
  if (isSymbol(value)) {
    return NAN;
  }
  return +value;
}
```

## 原理

`baseToNumber` 相较于 `Number()`，主要增加了对 `Symbol` 转换的优化，针对 `Symbol` 的特殊处理原因，我另起一篇文章讲解 [从 ECMAScript 中理解 Symbol 类型转换](/lodash-analysis/tips/symbolconvert.md)。

## 相关链接

* [从 ECMAScript 中理解 Symbol 类型转换](/lodash-analysis/tips/symbolconvert.md)
* [lodash 源码阅读 —— isSymbol](/lodash-analysis/lang/issymbol.md)