Is

isAbsolute

判断是否是绝对路径 EN: Return true when the provided path looks like an absolute path. Matches Unix absolute paths, Windows drive letters, or leading slashes/backslashes.

/**
 * 判断是否是绝对路径
 * @description EN: Return true when the provided path looks like an absolute path. Matches Unix absolute paths, Windows drive letters, or leading slashes/backslashes.
 * @param {string} url Path or URL string to test.
 * @returns {boolean} True when the path appears absolute.
 */

isArray

判断是否是数组 EN: Alias for Array.isArray.

/**
 * 判断是否是数组
 * @description EN: Alias for Array.isArray.
 */

isBlob

判断是否是blob EN: Check whether a value is a Blob object.

/**
 * 判断是否是blob
 * @description EN: Check whether a value is a Blob object.
 * @param o - candidate value
 * @returns boolean
 */

isBool

判断是否是boolean类型 EN: Check whether a value is a boolean.

/**
 * 判断是否是boolean类型
 * @description EN: Check whether a value is a boolean.
 * @param value - candidate value
 * @returns boolean
 */

isBottom

Determine whether the document is scrolled to the bottom (within distance). EN: Returns true when the document scroll position is at or near the bottom.

/**
 * Determine whether the document is scrolled to the bottom (within `distance`).
 * @description EN: Returns true when the document scroll position is at or near the bottom.
 * @param {number} [distance] Additional threshold in pixels.
 * @returns {boolean}
 */

isBrowser

判断当前环境是否具有浏览器全局（window） EN: True in environments where globalThis.window is defined (typical browsers).

/**
 * 判断当前环境是否具有浏览器全局（window）
 * @description EN: True in environments where `globalThis.window` is defined (typical browsers).
 */

isContainCn

判断是否包含中文 EN: Returns true if the input string contains any CJK Unified Ideographs (Chinese characters).

/**
 * 判断是否包含中文
 * @description EN: Returns true if the input string contains any CJK Unified Ideographs (Chinese characters).
 * @param s - input string
 * @returns boolean
 */

isDate

判断是否是日期格式 EN: Check whether a value is a Date instance.

/**
 * 判断是否是日期格式
 * @description EN: Check whether a value is a Date instance.
 * @param d - candidate value
 * @returns boolean
 */

isDef

判断元素不是undefined EN: Determine whether a value is defined (not undefined).

/**
 * 判断元素不是undefined
 * @description EN: Determine whether a value is defined (not undefined).
 * @param v - candidate value
 * @returns boolean
 */

isElement

判断元素是HTMLElement EN: Check whether a value is an HTMLElement.

/**
 * 判断元素是HTMLElement
 * @description EN: Check whether a value is an HTMLElement.
 * @param element - candidate value
 * @returns boolean
 */

isEqual

深度比较两个值是否相等 EN: Deep equality check for plain objects and arrays.

/**
 * 深度比较两个值是否相等
 * @description EN: Deep equality check for plain objects and arrays.
 * @param {any} o1 First value.
 * @param {any} o2 Second value.
 * @returns {boolean} True when values are deeply equal.
 */

isESModule

判断对象是ESModule EN: Detect if an object is an ES module (common __esModule or Symbol.toStringTag).

/**
 * 判断对象是ESModule
 * @description EN: Detect if an object is an ES module (common __esModule or Symbol.toStringTag).
 * @param obj - candidate object
 * @returns boolean
 */

isFalse

判断是否是false EN: Check whether a value is the boolean false.

/**
 * 判断是否是false
 * @description EN: Check whether a value is the boolean false.
 * @param v - candidate value
 * @returns boolean
 */

isFileType

判断文件类型 EN: Test if a filename/path has a given extension.

/**
 * 判断文件类型
 * @description EN: Test if a filename/path has a given extension.
 * @param { string } file 文件路径
 * @param { string } appendix 文件类型
 * @returns boolean
 */

isFn

判断是否是函数 EN: Check whether a value is a function.

/**
 * 判断是否是函数
 * @description EN: Check whether a value is a function.
 * @param o - candidate value
 * @returns boolean
 */

isIPv4

判断是否为 IPv4 地址 EN: Test whether a string is a valid IPv4 address.

/**
 * 判断是否为 IPv4 地址
 * @description EN: Test whether a string is a valid IPv4 address.
 * @param {string} ip Candidate IP string.
 * @returns {boolean}
 */

isIPv6

判断是否为 IPv6 地址 EN: Test whether a string matches common IPv6 patterns.

/**
 * 判断是否为 IPv6 地址
 * @description EN: Test whether a string matches common IPv6 patterns.
 * @param {string} ip Candidate IP address.
 * @returns {boolean}
 */

isIdCard

判断是否为身份证号（中国身份证格式的简单校验） EN: Heuristic check for Chinese ID card numbers (15 or 18 digits with possible ‘X’).

/**
 * 判断是否为身份证号（中国身份证格式的简单校验）
 * @description EN: Heuristic check for Chinese ID card numbers (15 or 18 digits with possible 'X').
 * @param {string} s Candidate ID string.
 * @returns {boolean}
 */

isLeapYear

判断是否为闰年 EN: Returns true for leap years (divisible by 400 or divisible by 4 and not by 100).

/**
 * 判断是否为闰年
 * @description EN: Returns true for leap years (divisible by 400 or divisible by 4 and not by 100).
 * @param {number} year Year number.
 * @returns {boolean}
 */

isMap

判断是否是 Map EN: Check whether a value is a Map instance.

/**
 * 判断是否是 Map
 * @description EN: Check whether a value is a Map instance.
 * @param {any} o Candidate value.
 * @returns {o is Map<any, any>} True if the internal [[Class]] is 'Map'.
 */

isMobile

判断是否是手机号 EN: Check whether a string looks like a mobile phone number (China-focused pattern).

/**
 * 判断是否是手机号
 * @description EN: Check whether a string looks like a mobile phone number (China-focused pattern).
 * @param s - phone number string
 * @returns boolean
 */

isNaN

判断是否为 NaN EN: Wraps Number.isNaN for a consistent helper.

/**
 * 判断是否为 NaN
 * @description EN: Wraps Number.isNaN for a consistent helper.
 * @param o Candidate value.
 * @returns {boolean}
 */

isNil

判断是否为 null 或 undefined EN: Returns true when the value is strictly null or undefined.

/**
 * 判断是否为 null 或 undefined
 * @description EN: Returns true when the value is strictly null or undefined.
 * @param {any} value Candidate value.
 * @returns {value is null | undefined}
 */

isNull

判断是否为 null EN: Check if a value is strictly null.

/**
 * 判断是否为 null
 * @description EN: Check if a value is strictly `null`.
 * @param {any} o Candidate value.
 * @returns {o is null} True when the value is exactly null.
 */

isNum

判断是否为数字 EN: Check whether a value has type ‘number’.

/**
 * 判断是否为数字
 * @description EN: Check whether a value has type 'number'.
 * @param {any} o Candidate value.
 * @returns {o is number}
 */

isObject

判断是否为对象类型 EN: Returns true for values with typeof ‘object’ (note: arrays/null are objects too).

/**
 * 判断是否为对象类型
 * @description EN: Returns true for values with typeof 'object' (note: arrays/null are objects too).
 * @param {any} value Candidate value.
 * @returns {boolean}
 */

isPlainObject

Check whether value is a plain object (i.e. {}).

/**
 * Check whether value is a plain object (i.e. {}).
 *
 * @param {any} o Candidate value.
 * @returns {o is Record<any, any>} True when `o` is a plain object.
 */

isPostCode

判断是否为邮政编码 EN: Simplified check for a 6-digit postal code (China-style).

/**
 * 判断是否为邮政编码
 * @description EN: Simplified check for a 6-digit postal code (China-style).
 * @param {string|number} s Candidate value.
 * @returns {boolean}
 */

isPromise

判断是否为 Promise EN: Check whether a value is a Promise instance.

/**
 * 判断是否为 Promise
 * @description EN: Check whether a value is a Promise instance.
 * @param {any} o Candidate value.
 * @returns {o is Promise<any>}
 */

isReg

判断是否是正则 EN: Check whether a value is a RegExp instance.

/**
 * 判断是否是正则
 * @description EN: Check whether a value is a RegExp instance.
 * @param o Candidate value.
 * @returns {o is RegExp} True when the value is a regular expression.
 */

isRelative

判断路径是否为相对路径 EN: Returns true for strings starting with ‘./’ or ’../‘.

/**
 * 判断路径是否为相对路径
 * @description EN: Returns true for strings starting with './' or '../'.
 * @param {string} str Path string.
 * @returns {boolean}
 */

isSameDay

判断两个日期是否为同一天 EN: Compares year, month and date to determine whether two Date

/**
 * 判断两个日期是否为同一天
 * @description EN: Compares year, month and date to determine whether two Date
 * objects represent the same calendar day.
 * @param {Date} dateLeft First date.
 * @param {Date} dateRight Second date.
 * @returns {boolean}
 */

isSet

判断是否为 Set EN: Check whether a value is a Set instance.

/**
 * 判断是否为 Set
 * @description EN: Check whether a value is a Set instance.
 * @param {any} o Candidate value.
 * @returns {o is Set<any>} True when the internal [[Class]] is 'Set'.
 */

isStr

判断是否为字符串 EN: Check whether a value has type ‘string’.

/**
 * 判断是否为字符串
 * @description EN: Check whether a value has type 'string'.
 * @param {any} o Candidate value.
 * @returns {o is string}
 */

isSupportCamera

判断当前环境是否支持摄像头采集（getUserMedia） EN: Heuristic detection for getUserMedia support across legacy vendor prefixes.

/**
 * 判断当前环境是否支持摄像头采集（getUserMedia）
 * @description EN: Heuristic detection for getUserMedia support across legacy vendor prefixes.
 * @returns {boolean}
 */

isSupportWebp

判断当前浏览器是否支持 WebP EN: Returns true when the current browser can encode a WebP

/**
 * 判断当前浏览器是否支持 WebP
 * @description EN: Returns true when the current browser can encode a WebP
 * data URL from a canvas (a common heuristic for WebP support).
 * @returns {boolean}
 */

isSymbol

判断是否为 symbol EN: Check whether a value has type ‘symbol’.

/**
 * 判断是否为 symbol
 * @description EN: Check whether a value has type 'symbol'.
 * @param {any} o Candidate value.
 * @returns {o is symbol}
 */

isTrue

判断是否是true EN: Check whether a value is the boolean literal true.

/**
 * 判断是否是true
/**
 * \u5224\u65ad\u662f\u5426\u662ftrue
 * @description EN: Check whether a value is the boolean literal true.
 * @param v - candidate value
 * @returns v is true
 */

isType

判断值是否匹配指定的类型标签 EN: Flexible type checker that accepts a shorthand type string

/**
 * 判断值是否匹配指定的类型标签
 * @description EN: Flexible type checker that accepts a shorthand type string
 * (like 'str', 'array', 'map') or multiple types separated by '|'. The
 * implementation delegates to specific `isX` helpers.
 * @param s Candidate value to test.
 * @param type Type label or pipe-separated labels.
 * @returns boolean True when any of the provided type labels match.
 */

isUndef

判断是否为 undefined EN: Returns true when the value is exactly undefined.

/**
 * 判断是否为 undefined
 * @description EN: Returns true when the value is exactly `undefined`.
 * @param o Candidate value.
 * @returns {o is undefined}
 */

isUrl

判断是否是 URL EN: Simple check whether a string looks like an HTTP/HTTPS URL.

/**
 * 判断是否是 URL
 * @description EN: Simple check whether a string looks like an HTTP/HTTPS URL.
 * @param {string} url The candidate URL string.
 * @returns {boolean} True if the string begins with "http://" or "https://".
 */

isVideo

判断是否为视频文件（基于扩展名） EN: Returns true when the filepath ends with a known video file extension.

/**
 * 判断是否为视频文件（基于扩展名）
 * @description EN: Returns true when the filepath ends with a known video file extension.
 * @param {string} filepath Path or filename.
 * @returns {boolean}
 */

isWeakMap

判断是否为 WeakMap EN: Check whether a value is a WeakMap instance.

/**
 * 判断是否为 WeakMap
 * @description EN: Check whether a value is a WeakMap instance.
 * @param {any} o Candidate value.
 * @returns {o is WeakMap<any, any>}
 */

isWeakSet

判断是否为 WeakSet EN: Check whether a value is a WeakSet instance.

/**
 * 判断是否为 WeakSet
 * @description EN: Check whether a value is a WeakSet instance.
 * @param {any} o Candidate value.
 * @returns {o is WeakSet<any>}
 */

isWin

判断是否为 Windows 平台 EN: Returns true when running on Windows (platform ‘win32’).

/**
 * 判断是否为 Windows 平台
 * @description EN: Returns true when running on Windows (platform 'win32').
 * @returns {boolean}
 */

isSocketUrl

判断是否为 WebSocket URL EN: Returns true for URLs that start with ws:// or wss://.

/**
 * 判断是否为 WebSocket URL
 * @description EN: Returns true for URLs that start with ws:// or wss://.
 * @param {string} url URL string.
 * @returns {boolean}
 */

isBase64

Check whether a string is a base64 data URL. EN: Validate whether a string is a data URL that contains base64-encoded content.

/**
 * Check whether a string is a base64 data URL.
 *
 * @description EN: Validate whether a string is a data URL that contains base64-encoded content.
 * @param {string} base64 Candidate string.
 * @returns {boolean} True when the string looks like a base64 data URL.
 */

isTrainNumber

判断是否为火车车次（简单校验） EN: Heuristic check for train numbers using common prefixes and 1-4 digits.

/**
 * 判断是否为火车车次（简单校验）
 * @description EN: Heuristic check for train numbers using common prefixes and 1-4 digits.
 * @param {string} s Candidate train number string.
 * @returns {boolean}
 */

isNameCn

判断是否为中文姓名（含·） EN: Test whether a string is a Chinese personal name (2-16 CJK chars or middle dot).

/**
 * 判断是否为中文姓名（含·）
 * @description EN: Test whether a string is a Chinese personal name (2-16 CJK chars or middle dot).
 * @param {string} s Candidate name string.
 * @returns {boolean}
 */

isNameEn

判断输入是否为英文姓名样式 EN: Simple heuristic to test for English name-like strings (letters and spaces, 2-22 chars).

/**
 * 判断输入是否为英文姓名样式
 * @description EN: Simple heuristic to test for English name-like strings (letters and spaces, 2-22 chars).
 * @param {string} s Candidate string.
 * @returns {boolean}
 */

isSoldierId

判断是否是军官证 EN: Heuristic check for a soldier/officer ID string. This function uses a simple regex and may not cover all real-world formats; it is intended as a lightweight validator rather than authoritative verification.

/**
 * 判断是否是军官证
 * @description EN: Heuristic check for a soldier/officer ID string. This function uses a simple regex and may not cover all real-world formats; it is intended as a lightweight validator rather than authoritative verification.
 * @param {string} s Candidate ID string.
 * @returns {boolean} True when the string matches the expected pattern.
 */

isVersion

判断是否为版本号 EN: Check whether a version string consists of dot-separated numeric parts.

/**
 * 判断是否为版本号
 * @description EN: Check whether a version string consists of dot-separated numeric parts.
 * @param {string} version Version string, e.g. '1.2.3'.
 * @returns {boolean}
 */

isDivElement

判断目标是否为 HTMLDivElement EN: Narrow type guard to detect

elements.

/**
 * 判断目标是否为 HTMLDivElement
 * @description EN: Narrow type guard to detect <div> elements.
 * @param {unknown} target Candidate value.
 * @returns {target is HTMLDivElement}
 */

isIFrameElement

判断目标是否为 HTMLIFrameElement EN: Narrow type guard for iframe elements.

/**
 * 判断目标是否为 HTMLIFrameElement
 * @description EN: Narrow type guard for iframe elements.
 * @param {unknown} target Candidate value.
 * @returns {target is HTMLIFrameElement}
 */

isImageElement

判断目标是否为 HTMLImageElement EN: Narrow type check to determine whether the target is an element.

/**
 * 判断目标是否为 HTMLImageElement
 * @description EN: Narrow type check to determine whether the target is an <img> element.
 * @param {unknown} target Candidate value.
 * @returns {target is HTMLImageElement}
 */

isNode

判断目标是否为 DOM Node EN: Returns true when the target is a DOM Node or looks like one (has numeric nodeType).

/**
 * 判断目标是否为 DOM Node
 * @description EN: Returns true when the target is a DOM Node or looks like one (has numeric nodeType).
 * @param {unknown} target Candidate value.
 * @returns {target is Node}
 */

isProxyDocument

判断目标是否为 ProxyDocument（特定实现的代理文档对象） EN: Type guard that tests for an object whose [[Class]] is ‘ProxyDocument’.

/**
 * 判断目标是否为 ProxyDocument（特定实现的代理文档对象）
 * @description EN: Type guard that tests for an object whose [[Class]] is 'ProxyDocument'.
 * @param {unknown} target Candidate value.
 * @returns {target is Document}
 */

isScriptElement

判断目标是否为 HTMLScriptElement EN: Narrow type guard for

/**
 * 判断目标是否为 HTMLScriptElement
 * @description EN: Narrow type guard for <script> elements.
 * @param {unknown} target Candidate value.
 * @returns {target is HTMLScriptElement}
 */

isShadowRoot

判断目标是否为 ShadowRoot EN: Type guard for ShadowRoot instances (if supported in environment).

/**
 * 判断目标是否为 ShadowRoot
 * @description EN: Type guard for ShadowRoot instances (if supported in environment).
 * @param {unknown} target Candidate value.
 * @returns {target is ShadowRoot}
 */

isStyleElement

判断目标是否为 HTMLStyleElement EN: Narrow type guard for

/**
 * 判断目标是否为 HTMLStyleElement
 * @description EN: Narrow type guard for <style> elements.
 * @param {unknown} target Candidate value.
 * @returns {target is HTMLStyleElement}
 */

isVue

判断文件路径是否是 Vue 单文件组件（.vue） EN: Simple check for filenames ending with ‘.vue’.

/**
 * 判断文件路径是否是 Vue 单文件组件（.vue）
 * @description EN: Simple check for filenames ending with '.vue'.
 * @param {string} src Path or filename.
 * @returns {boolean}
 */

isComment

判断是否为 HTML 注释 EN: Test whether a string looks like an HTML comment ().

/**
 * 判断是否为 HTML 注释
 * @description EN: Test whether a string looks like an HTML comment (<!-- ... -->).
 * Matches across newlines as well.
 * @param {string} s Input string.
 * @returns {boolean}
 */

isActive

判断当前页面是否处于活动（未被隐藏）状态 EN: Returns true when the document is currently visible/active

/**
 * 判断当前页面是否处于活动（未被隐藏）状态
 * @description EN: Returns true when the document is currently visible/active
 * (i.e. `document.hidden` is falsy).
 * @returns {boolean}
 */

isFile

判断是否是文件 EN: Check whether the input is a File (or file path on Node.js).

/**
 * 判断是否是文件
 * @description EN: Check whether the input is a File (or file path on Node.js).
 * @param o - Blob, File or string path
 * @returns boolean
 */