Logic

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• If-Else Conditions: Use {?} and {:else} to create conditional statements based on truthy values.
  
• Existence Check: Employ {?} to check if a key exists in the context by evaluating its truthy value.
  
• Negation Check: Utilize {^} to verify if a key does not exist in the context or if its value is falsy.

!> Note: In Igo Dust.js, an empty array [] evaluates to false in conditional statements.

Simple conditions

Render a section of text based on a simple condition.

// Template
Hello {?test}World{/test} OK.

// Data
{
  test: true
}

// Output
Hello World OK.

You can also render a section of text based on a condition applied to an attribute.

// Template
Hello {?test.a}World{/test.a} OK.

// Data
{
  test: { a: true }
}

// Output
Hello World OK.

Nested conditions

Render nested conditions based on multiple conditions.

// Template
{?world}World{?ok} OK{/ok}{/world}

// Data
{
  world: true,
  ok: true
}

// Output
World OK

Else

Render different text based on a condition, with an alternative if the condition is not met.

// Template
Hello {?test}World{:else}Good bye{/test} OK.

// Data
{
  test: false
}

// Output
Hello Good bye OK.

^ Condition

Render a section of text based on the absence of an attribute in the context.

// Template
Hello {^test.a}World{/test.a} OK.

// Data
{
  test: false
}

// Output
Hello World OK.

You can also use else with the ^ condition.

// Template
Hello {^test.a}World{:else}Planet{/test.a}.

// Data
{
  test: { a: true }
}

// Output
Hello Planet.

Function

Execute a function as a condition and render text based on its result.

// Template
Hello{?test world=w} World{/test}.

// Data
{
  w: true,
  test: (locals) => locals.world
}

// Output
Hello World.

Array

Igo Dust.js consider empty arrays as false.

// Template
OK {?users}{users.length} users{/users}.

// Data
{
  users: []
}

// Output
OK .

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