@shedevro/assert
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    0.0.14 • Public • Published

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    Assert

    Library provides assertion utility for better and safe coding.

    Features:

    • Right assertion return types:

      Assert.someFn(value): asserts value is string or Assert.is.someFn(value): value is string etc.

    • Assert functions can be chained with operators (is, all, nullOr, not)

    • throws WebUtilsAssertionError (extends from Error). Provides right stacktrace (especialy helpfull then coding with Angular to see links to .ts files)

    Installation

    npm i @shedevro/assert --save

    Usage

    First you should import the library

    import { Assert } from '@shedevro/assert';

    Custom error messages

    Each function can be customized with you own error message.

    Error message supports params injecting of assert functions arguments like input or expected values etc.

    Most often the order of params matches the function arguments order.

    For example:

    const someValue = 3;
    Assert.greaterThan(someValue, 10, 'This value should be greater than {2}, but got {1}');
    // throw error with message 'This value should be greater than 10, but got 3';

    Functions

    Then you can choice needed function.

    Operators

    Almost all functions can be chained with different operators.

    Moreover, you can combine them each other.

    • is – modifies assert functions to return true or false as a result
    • all – applies an assert function to a provided array
    • nullOr – runs assertion only if input value is defined
    • not – inverts assertion action

    For example:

    // is
    const someNumber = 10;
    if (Assert.is.range(someNumber, 10, 15)) {
      ...
    }
    
    
    // all
    class User {
      id: number;
      name: string;
    }
    
    const someArray = [new User(), new User];
    Assert.all.instanceOf(someArray, User);
    
    // ...futher actions
    
    
    // nullOr
    const someBoolean = null; // or undefined
    Assert.nullOr.boolean(someBoolean);
    // ...futher actions
    
    
    // not
    const someFunction = () => 123;
    Assert.not.throws(someFunction, TypeError);
    
    
    // combinations
    Assert.is.nullOr.not.emptyString('some string');
    Assert.not.endsWith('str', 'some suffix');
    Assert.nullOr.all.greaterThan([10, 11, 12, 13], 5);
    // ...and so on

    String Assertions

    Method Description
    string(value, message?: string) Ensures that value is a string
    emptyString(value, message?: string) Ensures that value is an empty string
    contains(value, subString: string, message?: string) Ensures that value contains substring
    startsWith(value, prefix: string, message?: string) Ensures that value starts with some prefix
    endsWith(value, suffix: string, message?: string) Ensures that value ends with some suffix

    Number Assertions

    Method Description
    number(value, message?: string) Ensures that value is a number
    natural(value, message?: string) Ensures that value is a natural number
    greaterThan(value, limit: number, message?: string) Ensures that value is greater than limit
    greaterThanOrEqual(value, limit: number, message?: string) Ensures that value is greater or equal to limit
    lessThan(value, limit: number, message?: string) Ensures that value is less than limit
    lessThanOrEqual(value, limit: number, message?: string) Ensures that value is less or equal to limit
    range(value, min: number, max: number, message?: string) Ensures that value is in range of min and max

    Boolean Assertions

    Method Description
    boolean(value, message?: string) Ensures that value is a boolean
    true(value, message?: string) Ensures that value is true
    false(value, message?: string) Ensures that value is false

    Object Assertions

    Method Description
    object(value, message?: string) Ensures that value is an object ({}, not Array or null)

    Function Assertions

    Method Description
    function(value, message?: string) Ensures that value is a function

    Array Assertions

    Method Description
    array(array, message?: string) Ensures that value is an array
    oneOf(value, values, message?: string) Ensures that value is one of values (string/number array)
    arrayLength(array, number: number, message?: string) Ensures that array length is equal to number
    arrayMinLength(array, limit: number, message?: string) Ensures that array length is not less than limit
    arrayMaxLength(array, limit: number, message?: string) Ensures that array length is not greater than limit
    arrayLengthBetween(array, min: number, max: number, message?: string) Ensures that array length is inside a min and max

    Instance Assertions

    Method Description
    instanceOf(value, instanceClass, message?: string) Ensures that value is an instance of some class
    instanceOfAny(value, instanceClasses, message?: string) Ensures that value is an instance of any class

    RexExp Assertions

    Method Description
    match(value, regExp: RegExp, message?: string) Ensures that value is match a regular expression

    Other Assertions

    Method Description
    defined(value, message?: string) Ensures that value is defined (not null, undefined or NaN)
    equal(value, expect, message?: string) Ensures that value is equal to expec (value === expect)
    throws(expression: () => any, errorClass?, message?: string) Ensures that expression throws some error

    Authors

    Shedevro

    All credits for great idea to @webmozart with his webmozart/assert for PHP!

    Contribute

    If you have ideas on how to improve this library, you are welcome!

    Please read readme of root project directory.

    License

    The content of this package is licensed under the MIT license.

    Install

    npm i @shedevro/assert

    DownloadsWeekly Downloads

    4

    Version

    0.0.14

    License

    MIT

    Unpacked Size

    87.9 kB

    Total Files

    64

    Last publish

    Collaborators

    • shedevro