JavaScript Advanced Programming (Third Edition) Learning notes (2)

Fifth Chapter

• Literal notation

var person = {    name:"a",    age:10,    5true// 数值属性名自动转换为字符串};

• The "First name" contains a space, so you cannot use dot notation to access it, but you can person["first name"
• Each item of an array can hold any type of data

varnewArray(20// 长度为20varnewArray("red""blue""green"// 包含三个字符串的数组

• Each time an item is added at the end of the array, its Length property is automatically updated to reflect this change

var c = ["red""blue"]c[99"green"// c.length = 100, 访问c[2] ~ c[98], 返回undefined

• Detects array value instanceof array for multiple global environments, cannot be judged accurately
• The Array.isarray (value) can
• Stack
  
  • Use the push () and Pop () methods of the array
• Queue
  
  • Shift () and push () methods. Shift gets the first item and deletes the first item.
  • Unshift (): Adds any item to the front of the array and returns the length of the new array
• Reverse () and sort ()
• Concat () can create a new array based on all the items in the current array
• Splice () method
  
  • Delete: Delete any number of items. Two parameters. The first represents the position of the first item to be deleted, and the second indicates the number of items to delete
  • Insert: You can insert any number of items to the specified location. Three parameters. Start position, 0, and item to insert
  • Replace: You can insert any number of items to the specified location. Three parameters.
• IndexOf () and LastIndexOf ()
• Iterative methods
  
  • Every () returns TRUE if each entry returns true
  • Filter () returns an array of true components
  • ForEach ()
  • Map () returns an array of result components
  • Some () returns true if any of the entries returns true
• Narrowing method
  
  • Reduce () Reduceright () (starting from the right)
  • Iterate over all items to build a value that is ultimately returned
• Date type
  
  • var now = new Date ();
  • Date.parse () accepts a character creation argument that represents a date, and then attempts to return the number of milliseconds from the corresponding date by this string
    
    • supported formats
      
      • 6/13/2004
      • January, 2004
      • Tue 2004 00:00:00 GMT-0700
      • yyyy-mm-ddthh:mm:ss.sssz
    • If the date cannot be represented, return nan
  • DATE.UTC () returns the number of milliseconds for the date
    
    • parameter is polygon, month (0 start), day, time, minute, second, millisecond. The first two must have the
  • Date Constructor Date.parse () and DATE.UTC (). The date and time are created based on the local time zone instead of GMT to create a
  • Date.now () returns the number of milliseconds that the date and time when the method was called
  • tolocalestring () returns the date and time in a format appropriate to the locale of the browser setting
• RegExp type
  
  • var expression =/Pattern/flags
  • Three kinds of signs
    
    • G: Will not stop when the first match is found
    • I: Case insensitive
    • M: Multiple lines. Continues to find the next line when it reaches the end of the text
  • The primary method for regexp an object is that the exec () parameter is the string to which the pattern is applied
    
    • Returns an array that contains additional properties index and input
    • In global mode, each call to exec returns the next occurrence
  • True when test () is matched

function sum1(num1, num2) {    return num1 + num2}varnullsum2(55// 10 仍然可以调用

• Understand why JS is not overloaded? Because the function defined later overrides the previous function.
• Function Internal Properties
  
  • Arguments
  • Callee: Points to the function that owns the arguments object. Arguments.callee
  • Caller: Caller. Arguments.callee.caller
• function methods
  
  • Apply ()
    
    • Two parameters, one is the scope in which the function is run, and the other is the parameter array
    • Calling a function in a specific scope
  • Call ()
    
    • List all the parameters.
• Packing BASIC type
  
  • The base type is not an object, logically there is no method. Automatically complete a series of processing in the background
    
    • Create an instance of type string
    • Invoking the development method on the instance
    • Destroy this instance

"some text"s1.color"red"alert(s1.color// undefined 实例已经被销毁

var num  = 10  alert (num . ToFixed ( Num ))   

• Number
  
  • ToFixed () A string representation of a numeric value that is returned by a specified number of decimal digits
  • Toexponential () formatting numeric scientific counts
  • Toprecision () may return a fixed size, possibly returning an exponent, depending on which format is most appropriate
• String
  
  • Concat () Stitching strings
  • IndexOf lastIndexOf
  • Trim () Remove all whitespace from the predecessor and suffix
  • toLowerCase touppercase uppercase and lowercase conversions
  • Match pattern matches, parameter is RegExp object or regular expression, return array
  • Replace the first argument regexp or a string, and the second is a string or function
  • Htmlescape escape less than sign, greater than, and number, double quotes
  • Split separates strings based on delimiters, resulting in arrays
• Global Object
  
  • URI encoding
  • encodeURI
    
    • For the entire URI, no special characters of the URI are encoded, such as colons,/,? #
  • encodeURIComponent
    
    • Used for a paragraph in a URI
  • decodeURI can only use encodeURI decoding, the same decodeuricomponent
• The eval () parameter is a JS statement string
• Math.random () 0~1, excluding 0 and 1
• Selectfrom () two parameters, Min and max (inclusive)

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JavaScript Advanced Programming (Third Edition) Learning notes (2)