返回限制在`lower`和`upper`之间的值

最新推荐文章于 2025-05-30 17:10:21 发布

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本文介绍了一个实用的函数，用于将数值限制在指定的上下限范围内。通过解析代码，我们了解到该函数如何处理各种输入，包括数字、符号和非数字类型，并确保返回的数值不会超出预设的边界。

/**
 * 返回限制在`lower`和`upper`之间的值
 * Clamps `number` within the inclusive `lower` and `upper` bounds.
 *
 * @param {number} number The number to clamp
 * @param {number} [lower] The lower bound
 * @param {number} upper The upper bound
 * @returns {number} Returns the clamped number.
 * @example
 *
 * clamp(-10, -5, 5)
 * // => -5
 *
 * clamp(10, -5, 5)
 * // => 5
 *
 */

const symbolTag = "[object Symbol]"
const NAN = 0 / 0
 
function isObjectLike(value) {
  return typeof value == "object" && value !== null
}
 
function isSymbol(value) {
  return (
    typeof value === "symbol" ||
    (isObjectLike(value) && Object.prototype.toString.call(value) === symbolTag)
  )
}
 
function toNumber(value) {
  if (typeof value === "number") {
    return value
  }
 
  if (isSymbol(value)) {
    return NAN
  }
 
  return Number(value)
}

function baseClamp(number, lower, upper) {
  if (number === number) {
    if (upper !== undefined) {
      number = number < upper ? number : upper
    }
    if (lower !== undefined) {
      number = number > lower ? number : lower
    }
  }
  return number
}

function clamp(number, lower, upper) {
  if (upper === undefined) {
    upper = lower
    lower = undefined
  }
  if (upper !== undefined) {
    upper = toNumber(upper)
    upper = upper === upper ? upper : 0
  }
  if (lower !== undefined) {
    lower = toNumber(lower)
    lower = lower === lower ? lower : 0
  }
  return baseClamp(toNumber(number), lower, upper)
}

export default clamp