nativescript-stringformat v2.3.4

NativeScript StringFormat

A NativeScript module for handling strings.

NativeScript Toolbox

This module is part of nativescript-toolbox.

License

MIT license

Platforms

• Android
• iOS

Installation

Run

tns plugin add nativescript-stringformat

inside your app project to install the module.

Demo

For quick start have a look at the demo/app/main-view-model.js file of the demo app to learn how it works.

Otherwise ...

Documentation

The full documentation can be found on readme.io.

Examples

Simple example

import StringFormat = require('nativescript-stringformat');

// "TM + MK"
var newStr1 = StringFormat.format("{0} + {1}",
                                  "TM",  // {0}
                                  "MK");  // {1}
                                 
// the alternative:
var newStr2 = StringFormat.formatArray("{0} + {1}",
                                       ["TM", "MK"]);

Custom order of arguments

import StringFormat = require('nativescript-stringformat');

// "Marcel Kloubert"
var newStr = StringFormat.format("{1} {0}",
                                 "Kloubert",   // {0}
                                 "Marcel");  // {1}

Functions as arguments

You can use functions that return the value that should be included into the target string:

import StringFormat = require('nativescript-stringformat');

// "23091979 + 5091979 = 28183958"
var newStr = StringFormat.format("{0} + {1} = {2}",
                                 23091979,  // {0}
                                 5091979,  // {1}
                                 function (index, args) {  // {2}
                                     return args[0] + args[1];  // 28183958
                                 });

The full signature of a function:

function (index, args, match, formatExpr, funcDepth) {
    return <THE-VALUE-TO-USE>;
}

Format providers

Separated by a : an argument can contain a format expression at the right side.

So you can define custom logic to convert an argument value.

Lets say we want to define a format provider that converts values to upper and lower case strings:

import StringFormat = require("nativescript-stringformat");

StringFormat.addFormatProvider(function(ctx) {    
    var toStringSafe = function() { 
        return ctx.value ? ctx.value.toString() : "";
    }
    
    if (ctx.expression === "upper") {
        // UPPER case
        ctx.handled = true;
        return toStringSafe().toUpperCase();
    }
    
    if (ctx.expression === "lower") {
        // LOWER case
        ctx.handled = true;
        return toStringSafe().toLowerCase();
    }
});

Now you can use the extended logic in your code:

import StringFormat = require('nativescript-stringformat');

// MARCEL kloubert
var newStr = StringFormat.format("{0:upper} {1:lower}",
                                 "Marcel", "KlOUBERT");

The ctx object of a provider callback has the following structure:

The parsed value has to be returned and ctx.handled has to be set to (true).

All upcoming format providers will be skipped if the value has been marked as "handled".

Helper functions and classes

Functions

Classes

StringBuilder

import StringFormat = require('nativescript-stringformat');

var builder = new StringFormat.StringBuilder();

for (var i = 0; i < 5; i++) {
    builder.appendFormat("Line #{1}: {0}", i, i + 1)
           .appendLine();
}

// "Line 1: 0
// Line 2: 1
// Line 3: 2
// Line 4: 3
// Line 5: 4"
var str = builder.toString();