util.ts — vue Source File

Source Code

export const emptyObject: Record<string, any> = Object.freeze({})

export const isArray = Array.isArray

// These helpers produce better VM code in JS engines due to their
// explicitness and function inlining.
export function isUndef(v: any): v is undefined | null {
  return v === undefined || v === null
}

export function isDef<T>(v: T): v is NonNullable<T> {
  return v !== undefined && v !== null
}

export function isTrue(v: any): boolean {
  return v === true
}

export function isFalse(v: any): boolean {
  return v === false
}

/**
 * Check if value is primitive.
 */
export function isPrimitive(value: any): boolean {
  return (
    typeof value === 'string' ||
    typeof value === 'number' ||
    // $flow-disable-line
    typeof value === 'symbol' ||
    typeof value === 'boolean'
  )
}

export function isFunction(value: any): value is (...args: any[]) => any {
  return typeof value === 'function'
}

/**
 * Quick object check - this is primarily used to tell
 * objects from primitive values when we know the value
 * is a JSON-compliant type.
 */
export function isObject(obj: any): boolean {
  return obj !== null && typeof obj === 'object'
}

/**
 * Get the raw type string of a value, e.g., [object Object].
 */
const _toString = Object.prototype.toString

export function toRawType(value: any): string {
  return _toString.call(value).slice(8, -1)
}

/**
 * Strict object type check. Only returns true
 * for plain JavaScript objects.
// ... (319 more lines)