Switch case with default in handlebars.js

问题

I want to implement a custom switch case with default value with the help of the Register Helper function in HandlebarsJs.

Example:

HTML:

<div>
    {{#switch value}} 
        {{#case 'a'}} A {{/case}} 
        {{#case 'b'}} B {{/case}} 
        {{#default 'C'}} {{/default}}
    {{/switch}}
</div>

JS:(The Register Helper function should work like the below pseudo code)

switch(val) {
  case 1:
     return 'A';
     break;
  case 2:
     return 'B';
     break;
  default:
     return 'C';
}

回答1:

Please go through the below examples, it will guide you step by step to add the switch case with default value and break in HandlebarsJs.

Use the link http://tryhandlebarsjs.com/ to test the code. (Give {} for Context)

Switch case

Handlebars Template:

<div>

        {{#switch 'a'}} 
            {{#case 'a'}} A {{/case}} 
            {{#case 'b'}} B {{/case}} 
        {{/switch}}

</div>

Register Helper functions:

Handlebars.registerHelper('switch', function(value, options) {
  this.switch_value = value;
  return options.fn(this);
});

Handlebars.registerHelper('case', function(value, options) {
  if (value == this.switch_value) {
    return options.fn(this);
  }
});

==========================================================================

Switch case with default:

Handlebars Template:

<div>

        {{#switch 'a'}} 
            {{#case 'a'}} A {{/case}} 
            {{#case 'b'}} B {{/case}}
            {{#default '188'}} {{/default}}
        {{/switch}}

</div>

Register Helper functions:

Handlebars.registerHelper('switch', function(value, options) {
  this.switch_value = value;
  return options.fn(this);
});

Handlebars.registerHelper('case', function(value, options) {
  if (value == this.switch_value) {
    return options.fn(this);
  }
});

Handlebars.registerHelper('default', function(value, options) {
    return true; ///We can add condition if needs
});

==========================================================================

Switch case with default and break

Handlebars Template:

<div>
        {{#switch 'a'}} 
            {{#case 'a'}} A {{/case}} 
            {{#case 'b'}} B {{/case}} 
            {{#default '188'}} {{/default}}
        {{/switch}}
</div>

Register Helper functions:

Handlebars.registerHelper('switch', function(value, options) {
  this.switch_value = value;
  this.switch_break = false;
  return options.fn(this);
});

Handlebars.registerHelper('case', function(value, options) {
  if (value == this.switch_value) {
    this.switch_break = true;
    return options.fn(this);
  }
});

Handlebars.registerHelper('default', function(value, options) {
   if (this.switch_break == false) {
     return value;
   }
});

回答2:

Just if you want to convert key to value.

module.exports = function(input, cases, values) {
  const caseArray = cases.split(',')
  const valueArray = values.split(',')
  const defaultValue = caseArray.length < valueArray.length ? valueArray[valueArray.length-1] : "";

  return caseArray.indexOf(input) > -1? valueArray[caseArray.indexOf(input)] : defaultValue 
};

{{switch "Y" "Y,N,D", "YES,NO,DELETED,-"}}  // YES
{{switch "Hi" "Y,N,D", "YES,NO,DELETED,-"}}  // -

来源：https://stackoverflow.com/questions/53398408/switch-case-with-default-in-handlebars-js