Overview

Some general helpers for Meteor Blaze including comparison, logic and numeric operators, logging, objects manipulation.

Installation

meteor add imajus:common-helpers

Related packages

• imajus:string-helpers
• imajus:html-helpers
• imajus:bootstrap-helpers

Contents

Package provides following global Blaze helpers:

• log(...args) – Just logs all argument passed to the browser console.
• field(object, path) – Extract a field from object by path (dot delimeters can be used):

{{field targetObject fieldName}}
{{field user 'email.0.address'}}

• not(val) – Equivalent of !val.
• eq(...args) – Returns true only if all arguments passed are equal (tested using == operator). Note: returns false if only one argument is passed.
• is(...args) – Returns true only if all arguments passed are identical (tested using === operator). Note: returns false if only one argument is passed.
• and(...args) – Returns true-like value if all arguments passed are true-like, return false-like otherwise (for using in conditions). Strictly speaking, helper returns first false-like value found in arguments or the last argument if all are true-like:

{{#if and currentUser someState somethingElse}}
  <div class="{{and someStringVariable 'replacement'}}">
{{/if}}

• or(...args) – Returns true-like value if any argument passed is true-like, return false-like if all arguments are false-like (for using in conditions). Strictly speaking, helper returns first true-like value found in arguments or the last argument if all are false-like:

{{#if or currentUser isEmulator}}
  <div class="{{or someStringVariable 'fallback'}}">
{{/if}}

• sum(...args) – Sums all arguments passed using += operator (can also be used for string concatenation, but for that better to use concat from imajus:string-helpers):

<div>{{sum price fee tax}}</div>

• sub(...args) - Subtract arguments starting from 2nd from 1st.

<div>{{sub capacity used}}</div>

• positive(...args) – Returns true only if all passed arguments are greater than zero, returns false otherwise.

{{#if positive balance}}...{{/if}}

• negative(...args) – Returns true only if all passed arguments are less than zero, returns false otherwise.

{{#if negative balance}}...{{/if}}

• gt(...args, { comp }) – Returns true only if all passed arguments are greater than comp, returns false otherwise.

{{#if gt 9 balance comp=price}}...{{/if}}

• gt(...args, { comp }) – Returns true only if all passed arguments are greater than or equal to comp, returns false otherwise.

{{#if gte 10 balance comp=price}}...{{/if}}

• lt(...args, { comp }) – Returns true only if all passed arguments are less than comp, returns false otherwise.

{{#if lt 100 price comp=balance}}...{{/if}}

• lte(...args, { comp }) – Returns true only if all passed arguments are less than or equal to comp, returns false otherwise.

{{#if lte 99 price comp=balance}}...{{/if}}

• nullOrUndefined(...args) – Returns true only if all passed arguments are null or undefined.
• when(...) - Analogue of ternary operator. Has two forms:
  1. when(cond, yes, no) - Returns yes value when cond is true-like, returns no value otherwise.
  2. when(...conds, { yes, no }) - Returns yes value when all conds are true-like, returns no value if any of conds false-like. This form allows not to pass yes and/or no at all, in which case undefined will be used for missing value.

<div class="{{when loaded 'loaded' 'loading'}}">
<div class="{{when loaded 'loaded'}}">
<div class="{{when loaded no='loading'}}">
<div class="{{when loaded ready subsReady yes='ready' no='loading'}}">
<div class="{{when loaded ready subsReady yes='ready'}}">
<div class="{{when loaded ready subsReady no='loading'}}">

• chunk(array, size) – Splits array into chunks of equal size and return array of arrays. The latest chunk may have less elements than previous depending on the length of original array.

{{#each group in chunk items 3}}
  <div class="row">
    {{#each item in group}}
      <div class="col">...</div>
    {{/each}}
  </div>
{{/each}}