CoffeeScript-Splat



在前面的章节中,我们已经了解了如何定义函数,调用函数并将参数传递给它。通常,我们可以将固定数量的参数传递给函数。在编程时,我们可能会遇到需要将变量参数传递给这些函数的情况。在JavaScript中,我们使用对象来接受可变数量的参数的函数。

CoffeeScript提供了一个称为splats的功能,可以将多个参数传递给函数。我们在函数中使用splats,方法是在参数名称后放置三个点,并用表示

句法

下面给出的是使用splats在函数中接受多个参数的语法。

my_function = (arguments...)->
   ............
   ............
   ............

以下是使用splats在函数中接受多个参数的示例。在这里,我们使用splats定义了一个名为indian_team()的函数。我们称此函数三次,每次调用时将同时传递4名球员,6名球员和全班球员。由于我们在函数定义中使用了splats,因此每次调用它都接受可变数量的参数。将此代码保存在名称为splats_definition.coffee的文件中

indian_team = (first, second, others...) ->
  Captain = first
  WiseCaptain = second
  team  = others
  console.log "Captain: " +Captain
  console.log "Wise captain: " +WiseCaptain
  console.log "Other team members: " +team

#Passing 4 arguments
console.log "############## Four Players ############"
indian_team "Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma"

#Passing 6 arguments
console.log "############## Six Players ############"
indian_team "Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan"
  
#Passing full squad
console.log "############## Full squad #############"
indian_team "Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan", "Ravindra Jadeja", "Axar Patel", "Jasprit Bumrah", "Umesh Yadav", "Harbhajan Singh", "Ashish Nehra", "Hardik Pandya", "Suresh Raina", "Yuvraj Singh", "Ajinkya Rahane"

打开命令提示符并编译.coffee文件,如下所示。

c:\> coffee -c splats_definition.coffee

编译时,它将为您提供以下JavaScript。

// Generated by CoffeeScript 1.10.0
(function() {
  var indian_team,
    slice = [].slice;

  indian_team = function() {
    var Captain, WiseCaptain, first, others, second, team;
    first = arguments[0], second = arguments[1], others = 3 <= arguments.length ? slice.call(arguments, 2) : [];
    Captain = first;
    WiseCaptain = second;
    team = others;
    console.log("Captain: " + Captain);
    console.log("Wise captain: " + WiseCaptain);
    return console.log("Other team members: " + team);
  };

  console.log("############## Four Players ############");

  indian_team("Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma");

  console.log("############## Six Players ############");

  indian_team("Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan");

  console.log("############## Full squad #############");

  indian_team("Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan", "Ravindra Jadeja", "Axar Patel", "Jasprit Bumrah", "Umesh Yadav", "Harbhajan Singh", "Ashish Nehra", "Hardik Pandya", "Suresh Raina", "Yuvraj Singh", "Ajinkya Rahane");

}).call(this); 

现在,再次打开命令提示符,然后运行CoffeeScript文件,如下所示。

c:\> coffee splats_definition.coffee

执行时,CoffeeScript文件将产生以下输出。

############## Four Players ############
Captain: Mahendra Singh Dhoni
Wise captain: Virat Kohli
Other team members: Shikhar Dhawan,Rohit Sharma
############## Six Players ############
Captain: Mahendra Singh Dhoni
Wise captain: Virat Kohli
Other team members: Shikhar Dhawan,Rohit Sharma,Gurkeerat Singh Mann,Rishi Dhawan
############## Full squad #############
Captain: Mahendra Singh Dhoni
Wise captain: Virat Kohli
Other team members: Shikhar Dhawan,Rohit Sharma,Gurkeerat Singh Mann,Rishi Dhawan,Ravindra Jadeja,Axar Patel,Jasprit Bumrah,Umesh Yadav,Harbhajan Singh,Ashish Nehra,Hardik Pandya,Suresh Raina,Yuvraj Singh,Ajinkya Rahane 

使用Splats调用函数

我们还可以使用splats调用函数。为此,我们必须创建一个数组,其中包含需要传递给函数的元素,并且必须通过传递后缀三个点的数组来调用函数,如下所示。

my_function values...

以下是使用splats调用函数的示例。将此代码保存在名为splats_call.coffee的文件中

indian_team = (first, second, others...) ->
  Captain = first
  WiseCaptain = second
  team  = others
  console.log "Captain: " +Captain
  console.log "Wise captain: " +WiseCaptain
  console.log "Other team members: " +team

squad = [
   "Mahendra Singh Dhoni"
   "Virat Kohli"
   "Shikhar Dhawan"
   "Rohit Sharma"   
   "Gurkeerat Singh Mann"
   "Rishi Dhawan"
   "R Ashwin"
   "Ravindra Jadeja"
   "Axar Patel"
   "Jasprit Bumrah"
   "Umesh Yadav"
   "Harbhajan Singh"
   "Ashish Nehra"
   "Hardik Pandya"
   "Suresh Raina"
   "Yuvraj Singh"
   "Ajinkya Rahane"
 ]

indian_team squad...

打开命令提示符并编译.coffee文件,如下所示。

c:\> coffee -c splats_call.coffee

编译时,它将为您提供以下JavaScript。

// Generated by CoffeeScript 1.10.0
(function() {
  var indian_team, squad,
    slice = [].slice;

  indian_team = function() {
    var Captain, WiseCaptain, first, others, second, team;
    first = arguments[0], second = arguments[1], others = 3 <= arguments.length ? slice.call(arguments, 2) : [];
    Captain = first;
    WiseCaptain = second;
    team = others;
    console.log("Captain: " + Captain);
    console.log("Wise captain: " + WiseCaptain);
    return console.log("Other team members: " + team);
  };

  squad = ["Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan", "R Ashwin", "Ravindra Jadeja", "Axar Patel", "Jasprit Bumrah", "Umesh Yadav", "Harbhajan Singh", "Ashish Nehra", "Hardik Pandya", "Suresh Raina", "Yuvraj Singh", "Ajinkya Rahane"];

  indian_team.apply(null, squad);

}).call(this);

现在,再次打开命令提示符,然后运行CoffeeScript文件,如下所示。

c:\> coffee splats_call.coffee

执行时,CoffeeScript文件将产生以下输出。

Captain: Mahendra Singh Dhoni
Wise captain: Virat Kohli
Other team members: Shikhar Dhawan,Rohit Sharma,Gurkeerat Singh Mann,Rishi Dhawan,R Ashwin,Ravindra Jadeja,Axar Patel,Jasprit Bumrah,Umesh Yadav,Harbhajan Singh,Ashish Nehra,Hardik Pandya,Suresh Raina,Yuvraj Singh,Ajinkya Rahane

带有尾标的Splat

我们还可以将尾随参数传递给splat。在下面的例子中,我们已经通过了图示的名字命名的最后一个拖尾的说法。将此示例保存在名称为tailing_arguments.coffee的文件中

indian_team = (first, second, others..., last) ->
  Captain = first
  WiseCaptain = second
  team  = others
  Wicketkeeper =last
  console.log "Captain: " +Captain
  console.log "Wise captain: " +WiseCaptain
  console.log "Wicket keeper is:"+last
  console.log "Other team members: " +team  
  
squad = [
   "Mahendra Singh Dhoni"
   "Virat Kohli"
   "Shikhar Dhawan"
   "Rohit Sharma"   
   "Gurkeerat Singh Mann"
   "Rishi Dhawan"
   "R Ashwin"
   "Ravindra Jadeja"
   "Axar Patel"
   "Jasprit Bumrah"
   "Umesh Yadav"
   "Harbhajan Singh"
   "Ashish Nehra"
   "Hardik Pandya"
   "Suresh Raina"
   "Yuvraj Singh"
   "Ajinkya Rahane"
 ]

indian_team squad...

打开命令提示符并编译.coffee文件,如下所示。

c:\> coffee -c tailing_arguments.coffee

编译时,它将为您提供以下JavaScript。

// Generated by CoffeeScript 1.10.0
(function() {
  var indian_team, squad,
    slice = [].slice;

  indian_team = function() {
    var Captain, Wicketkeeper, WiseCaptain, first, i, last, others, second, team;
    first = arguments[0], second = arguments[1], others = 4 <= arguments.length ? slice.call(arguments, 2, i = arguments.length - 1) : (i = 2, []), last = arguments[i++];
    Captain = first;
    WiseCaptain = second;
    team = others;
    Wicketkeeper = last;
    console.log("Captain: " + Captain);
    console.log("Wise captain: " + WiseCaptain);
    console.log("Wicket keeper is:" + last);
    return console.log("Other team members: " + team);
  };

  squad = ["Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan", "R Ashwin", "Ravindra Jadeja", "Axar Patel", "Jasprit Bumrah", "Umesh Yadav", "Harbhajan Singh", "Ashish Nehra", "Hardik Pandya", "Suresh Raina", "Yuvraj Singh", "Ajinkya Rahane"];

  indian_team.apply(null, squad);

}).call(this);

现在,再次打开命令提示符,然后运行CoffeeScript文件,如下所示。

c:\> coffee tailing_arguments.coffee

执行时,CoffeeScript文件将产生以下输出。

Captain: Mahendra Singh Dhoni
Wise captain: Virat Kohli
Wicket keeper is:Ajinkya Rahane
Other team members: Shikhar Dhawan,Rohit Sharma,Gurkeerat Singh Mann,Rishi Dhawan,R Ashwin,Ravindra Jadeja,Axar Patel,Jasprit Bumrah,Umesh Yadav,Harbhajan Singh,Ashish Nehra,Hardik Pandya,Suresh Raina,Yuvraj Singh

对Splats的理解

在函数,我们还可以使用理解来迭代splat的元素,如以下示例所示。将此代码保存在名称为splats_comprehensions.coffee的文件中

indian_team = (first, second, others...) ->
  Captain = first
  WiseCaptain = second
  team  = others
  console.log "Captain: " +Captain
  console.log "Wise captain: " +WiseCaptain
  console.log "Other team members:: "
  console.log member for member in others

squad = [
   "Mahendra Singh Dhoni"
   "Virat Kohli"
   "Shikhar Dhawan"
   "Rohit Sharma"   
   "Gurkeerat Singh Mann"
   "Rishi Dhawan"
   "R Ashwin"
   "Ravindra Jadeja"
   "Axar Patel"
   "Jasprit Bumrah"
   "Umesh Yadav"
   "Harbhajan Singh"
   "Ashish Nehra"
   "Hardik Pandya"
   "Suresh Raina"
   "Yuvraj Singh"
   "Ajinkya Rahane"
 ]

indian_team squad...

打开命令提示符并编译.coffee文件,如下所示。

c:\> coffee -c splats_comprehensions.coffee

编译时,它将为您提供以下JavaScript。

// Generated by CoffeeScript 1.10.0
(function() {
  var indian_team, squad,
    slice = [].slice;

  indian_team = function() {
    var Captain, WiseCaptain, first, i, len, member, others, results, second, team;
    first = arguments[0], second = arguments[1], others = 3 <= arguments.length ? slice.call(arguments, 2) : [];
    Captain = first;
    WiseCaptain = second;
    team = others;
    console.log("Captain: " + Captain);
    console.log("Wise captain: " + WiseCaptain);
    console.log("Other team members:: ");
    results = [];
    for (i = 0, len = others.length; i < len; i++) {
      member = others[i];
      results.push(console.log(member));
    }
    return results;
  };

  squad = ["Mahendra Singh Dhoni", "Virat Kohli", "Shikhar Dhawan", "Rohit Sharma", "Gurkeerat Singh Mann", "Rishi Dhawan", "R Ashwin", "Ravindra Jadeja", "Axar Patel", "Jasprit Bumrah", "Umesh Yadav", "Harbhajan Singh", "Ashish Nehra", "Hardik Pandya", "Suresh Raina", "Yuvraj Singh", "Ajinkya Rahane"];

  indian_team.apply(null, squad);

}).call(this);

现在,再次打开命令提示符,然后运行CoffeeScript文件,如下所示。

c:\> coffee splats_comprehensions.coffee

执行时,CoffeeScript文件将产生以下输出。

Captain: Mahendra Singh Dhoni
Wise captain: Virat Kohli
Other team members::
Shikhar Dhawan
Rohit Sharma
Gurkeerat Singh Mann
Rishi Dhawan
R Ashwin
Ravindra Jadeja
Axar Patel
Jasprit Bumrah
Umesh Yadav
Harbhajan Singh
Ashish Nehra
Hardik Pandya
Suresh Raina
Yuvraj Singh
Ajinkya Rahane

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