@codefresh-io/tevale

v0.9.4

Published

2 months ago

Tevale is the tiny evaluator of expressions, which accepts a set of variables (named objects with properties) and an expression, validates its syntax and evaluates the expression.

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tevale

Tevale is the tiny evaluator of expressions, which accepts a set of variables (named objects with properties) and an expression, validates its syntax and evaluates the expression.

Developed in Codefresh.

Its goal is to allow the evaluations of expressions (in a variable context) so as to generate a boolean true/false result. It was designed to be embeded into scripts that contain various entities and require the evaluation of an expression to make a yes/no decision.

Features

Validation and evaluation of expressions
Supports variables in expressions, including object variables (nesting)
Supports popular functions and operators for number and string manipulation
Supports string searching and regexp matching functions

Installation

$ npm install cf-expression-evaluator --save

Usage

const tevale = require('tevale');
const variables = {
    "author": {
        "name": "Alon Diamant",
        "homepage": "http://www.alondiamant.com",
        "github": {
            "repositories": 12,
            "url": "http://www.github.com/advance512"
        },
    },
    "company": {
        "name": "Codefresh",
        "homepage": "http://www.codefresh.io",
        "phoneNumber": "+972-99-999-9999"
    }
}

console.log(
    tevale.evaluateExpression(
        'match(author.name, "alon", true) && ' +
        'author.github.repositories > 10 && ' +
        'Number(substring(company.phoneNumber, 1, 4)) / 2 == 486',
        variables
    )
);

Reference

Types

|Type|Example|True/False| |----|:-----:|:--------:| |String|"hello"'there'|Empty string is false: ''Non-empty string is true: 'something'String comparison is lexicographic| |Number|53.41.79E+308|0 is falseany non-0 number is true| |Boolean|truefalse|true is truefalse is false| |null|Null|always false|

Variables and Members

You can then use the members of each variable.
To access variables that have a non-standard (i.e. only alphanumeric and _ characters) names, use the Variable() function.
To access variable members that have a non-standard (i.e. only alphanumeric and _ characters) names, use the Member() function.

Unary Operators

|Operator|Operation| |--------|:-------:| |-|Negation of numbers| |!|Logical NOT|

Binary Operators

|Operator|Operation| |--------|:-------:| |+|Add, String Concatenation| |-|Subtract| |*|Multiply| |/|Divide| |%|Modulus| |&&|Logical AND| ||||Logical OR|

Comparisons

|Operator|Operation| |--------|:-------:| |==|Equal| |!=|Not equal| |>|Greater than| |>=|Greater than or equal| |<|Less than| |>=|Less than or equal|

Functions

|Function Name|Parameters|Return value|Example| |-------------|:--------:|:----------:|:-----:| |String|0: number or string|string of input value|String(40) == '40'| |Number|0: number or string|number of input value|Number('50') == 50Number('hello') is invalid| |Boolean|0: number or string|boolean of input value|Boolean('123') == trueBoolean('') == falseBoolean(583) == trueBoolean(0) == false| |round|0: number|rounded number|round(1.3) == 1round(1.95) == 2| |floor|0: number|number rounded to floor|floor(1.3) == 1floor(1.95) == 1| |upper|0: string|string in upper case|upper('hello') == 'HELLO'| |lower|0: string|string in lower case|lower('BYE BYE') == 'bye bye'| |trim|0: string|trimmed string|trim(" abc ") == "abc"| |trimLeft|0: string|left trimmed string|trimLeft(" abc ") == "abc "| |trimRight|0: string|right trimmed string|trimRight(" abc ") == " abc"| |replace|0: string - main string1: string - substring to find2: string - substring to replace|replace all instances of the substring (1) in the main string (0) with the substring (2)|replace('hello there', 'e', 'a') == 'hallo thara'| |substring|0: string - main string1: string - index to start2: string - index to end|returns a substring of a string|substring("hello world", 6, 11) == "world"| |length|string|length of a string|length("gump") == 4| |includes|0: string - main string1: string - string to search for|whether a search string is found inside the main string|includes("codefresh", "odef") == true| |indexOf|0: string - main string1: string - string to search for|index of a search string if it is found inside the main string|indexOf("codefresh", "odef") == 1| |match|0: string - main string1: string - regular expression string, JS style2: boolean - ignore case|search for a regular expression inside a string, ignoring or not ignoring case|match("hello there you", "..ll.", false) == truematch("hello there you", "..LL.", false) == falsematch("hello there you", "hell$", true) == falsematch("hello there you", "^hell", true) == truematch("hello there you", "bye", false) == false| |Variable|string|Lookup the value of a variable|Variable('someVariable')| |Member|0: string - variable name1: string - member name|Lookup the value of a member of a variable|Member('someVariable', 'workingDirectory')|

Examples

Using the variables:

const exampleVariables = {
    'somePositiveNumericValue': 123,
    'someZeroValue': 0,
    'someNegativeNumericValue': -50,
    'stringValue': 'hello',
    'emptyStringValue': '',
    'longStringValue': 'mA26EKMPupgvp6XYlGAVJZKv6yvaD3aobXMyExvyMBa2Hi9LlJXTUaBveMR9ErHtSfXNHHW5xAKbz2DVfBOqQ8CaSMNMQRBrJRpEpsO7FygKZmKpKHvvtPviOTfyUE0HGhnSPYHb9Hbz1CMxab4T0iQxPLCwrg57Qi0sTW1sJhVSygD9ivCfhJwJmD9PNb8bV0rJJ9aWp84LeaC7PDkj5hAozkrrJVA5hozLSXGZb0A4JLKiPOe9ITvxcIqvPNaMPA2SF4AQasE01TeGyuHQICuAMTGFFAP9y0HJBm7N0XmU',
    'trueBooleanValue': true,
    'falseBooleanValue': false,
    'nullBooleanValue': null,
    'simpleObjectValue': {
        'someNumericValue': 123,
        'someStringValue': 'hello there',
        'someNullValue': null,
        'someBooleanValue': false,
    },
    'complexObjectValue': {
        'internalObjectValue': {
            'someNumericValue': 123,
            'someStringValue': 'hello there',
            'someNullValue': null,
            'someBooleanValue': false,
        },
    },
    'superComplexObjectValue': {
        'internalObjectValue': {
            'moreInternalObjectValue': {
                'someNumericValue': 123,
                'someStringValue': 'hello there',
                'someNullValue': null,
                'someBooleanValue': false,
            },
        },
    },
    'typicalObjectValue': {
        'branch_name': 'master',
        'working_dir': '/tmp/whatever',
        'success': true,
    },
    'emptyObjectValue': {},

    'author': {
        'name': 'Alon Diamant',
        'homepage': 'http://www.alondiamant.com',
        'github': {
            'repositories': 12,
            'url': 'http://www.github.com/advance512',
        },
    },
    'company': {
        'name': 'Codefresh',
        'homepage': 'http://www.codefresh.io',
        'phoneNumber': '+972-99-999-9999',
    },
};

The result for the following expressions is:

| Expression | Result or Error Message | | ------------- |:-------------:| |''|false| |'null'|false| |'false'|false| |'1234'|true| |'-1234'|true| |'0000000'|false| |'""'|false| |'"asdasd"'|true| |''asdasd''|true| |'asdasd'|Unexpected "`" at character 0| |'somePositiveNumericValue'|true| |'someZeroValue'|false| |'someNegativeNumericValue'|true| |'stringValue'|true| |'emptyStringValue'|false| |'longStringValue'|true| |'trueBooleanValue'|true| |'falseBooleanValue'|false| |'!falseBooleanValue'|true| |'nullBooleanValue'|false| |'invalidIdentifer'|Invalid identifier: 'invalidIdentifer'| |'somePositiveNumericValue > someZeroValue'|true| |'somePositiveNumericValue < someZeroValue'|false| |'somePositiveNumericValue >= someZeroValue'|true| |'somePositiveNumericValue <= someZeroValue'|false| |'somePositiveNumericValue >= somePositiveNumericValue'|true| |'somePositiveNumericValue <= somePositiveNumericValue'|true| |'longStringValue > emptyStringValue'|true| |'longStringValue < emptyStringValue'|false| |'longStringValue == longStringValue'|true| |'longStringValue === longStringValue'|Invalid binary operator: ===| |'longStringValue > stringValue'|true| |'longStringValue < stringValue'|false| |'simpleObjectValue.someNumericValue == 123'|true| |'simpleObjectValue.someNumericValue'|true| |'simpleObjectValue.someNullValue'|false| |'simpleObjectValue.someBooleanValue'|false| |'simpleObjectValue.someBooleanValue == false'|true| |'complexObjectValue.internalObjectValue.someNumericValue == 123'|true| |'complexObjectValue.internalObjectValue.someNumericValue'|true| |'complexObjectValue.internalObjectValue.someNullValue'|false| |'complexObjectValue.internalObjectValue.someBooleanValue'|false| |'complexObjectValue.internalObjectValue.someBooleanValue == false'|true| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.someNumericValue == 123'|true| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.someNumericValue'|true| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.someNullValue'|false| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.someBooleanValue'|false| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.someBooleanValue == false'|true| |'typicalObjectValue.branch_name == "master"'|true| |'typicalObjectValue.working_dir == "/var/tmp"'|false| |'!!typicalObjectValue.success'|true| |'typicalObjectValue.success == true'|true| |'typicalObjectValue.nonExistant'|Undefined identifier member: 'nonExistant'| |'typicalObjectValue'|Cannot evaluate object variable directly| |'emptyObjectValue.someBooleanValue == false'|Undefined identifier member: 'someBooleanValue'| |'emptyObjectValue.someBooleanValue'|Undefined identifier member: 'someBooleanValue'| |'emptyObjectValue'|Cannot evaluate object variable directly| |'superComplexObjectValue.'|Unexpected at character 24| |'superComplexObjectValue..'|Unexpected . at character 24| |'superComplexObjectValue.internalObjectValue'|Cannot evaluate object variable directly| |'superComplexObjectValue.internalObjectValue.'|Unexpected at character 44| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue'|Cannot evaluate object variable directly| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.'|Unexpected at character 68| |'superComplexObjectValue.internalObjectValue.moreInternalObjectValue.nonExistant'|Undefined identifier member: 'nonExistant'| |'superComplexObjectValue.internal Object Value.moreInternalObjectValue.someNumericValue'|Cannot handle compound expressions.| |'superComplexObjectValue.internalObject.Value.moreInternalObjectValue.someNumericValue'|Undefined identifier member: 'internalObject'| |'somePositiveNumericValue > null'|The operator > cannot be used with number,null. It can only be used with the types: number,string| |'somePositiveNumericValue < stringValue'|The operator < cannot be used with number,string. It can only be used with the types: number,string| |'somePositiveNumericValue > true'|The operator > cannot be used with number,boolean. It can only be used with the types: number,string| |'somePositiveNumericValue > simpleObjectValue'|The operator > cannot be used with number,object. It can only be used with the types: number,string| |'complexObjectValue > simpleObjectValue'|The operator > cannot be used with object,object. It can only be used with the types: number,string| |'false > null'|The operator > cannot be used with boolean,null. It can only be used with the types: number,string| |'false > true'|The operator > cannot be used with boolean,boolean. It can only be used with the types: number,string| |'someStringValue > null'|Invalid identifier: 'someStringValue'| |'internalObjectValue.someNumericValue > null'|Invalid identifier: 'internalObjectValue'| |'typicalObjectValue.working_dir > 82'|The operator > cannot be used with string,number. It can only be used with the types: number,string| |'typicalObjectValue.working_dir > complexObjectValue.internalObjectValue.someNumericValue'|The operator > cannot be used with string,number. It can only be used with the types: number,string| |'(somePositiveNumericValue > someZeroValue)'|true| |'(somePositiveNumericValue >= someZeroValue) && true'|true| |'(longStringValue > emptyStringValue) && (longStringValue >= emptyStringValue)'|true| |'((longStringValue > emptyStringValue) && (longStringValue >= emptyStringValue))'|true| |'(longStringValue > emptyStringValue && (longStringValue >= emptyStringValue))'|true| |'60 > 35 && (50 > 22 && ((90 > 33) && ((26 > 10) && 15 > 30)) || (80 > 32))'|true| |'60 > 35 && (50 > 22 && ((90 > 33) && ((26 > 10) && 15 > 30)) || (80 < 32))'|false| |'60 > 35 && (50 > 22 && ((90 > 33) && ((26 > 10) && 15 > 30)) || (somePositiveNumericValue > 32))'|true| |'60 > 35 && (50 > 22 && ((90 > 33) && ((26 > 10) && 15 > 30)) || (somePositiveNumericValue < 32))'|false| |'somePositiveNumericValue / someZeroValue'|Division of 123 by 0| |'somePositiveNumericValue % someZeroValue'|Modulo of 123 by 0| |'somePositiveNumericValue / somePositiveNumericValue'|true| |'9007199254740991 * 9007199254740991'|true| |'1.231 * 5.2342'|true| |'+true'|The operator + cannot be used with boolean. It can only be used with the types: number| |'+234'|true| |'~234'|Invalid unary operator: ~| |'555+true'|The operator + cannot be used with number,boolean. It can only be used with the types: number,string| |'23423-223'|true| |'123-123'|false| |'!true'|false| |'!!true'|true| |'!!!!!!!!!!true'|true| |'!33'|false| |'!!33'|true| |'!0'|true| |'!!0'|false| |'55 % 10 == 5'|true| |'1.79E+308 * 1.79E+308'|Numeric overflow| |'15 | 33'|Invalid binary operator: || |'5555 @ 33333'|Unexpected "@" at character 5| |'5555 $ 33333'|Cannot handle compound expressions.| |'5555 \ 33333'|Unexpected "" at character 5| |'5555 : 33333'|Unexpected ":" at character 5| |'5555 :::: 33333'|Unexpected ":" at character 5| |'stringValue / 5'|The operator / cannot be used with string,number. It can only be used with the types: number| |'stringValue / stringValue'|The operator / cannot be used with string,string. It can only be used with the types: number| |'stringValue + 5'|The operator + cannot be used with string,number. It can only be used with the types: number,string| |'stringValue + 5'|The operator + cannot be used with string,number. It can only be used with the types: number,string| |'this'|keyword 'this' not supported.| |'5 > 2 ? 4 : 1'|Trinary operator (?:) currently not supported.| |'[1, 2, 3]'|Array literals ([1, 2, 3]) currently not supported.| |'upper(stringValue)'|true| |'substring(stringValue, 2, 4)'|true| |'substring(stringValue, 20, 40)'|false| |'upper()'|Expected 1 arguments for function 'upper'.| |'lower(123)'|Invalid argument #0 of type number for function 'lower': expected string| |'lower("asd", 3, 5)'|Expected 1 arguments for function 'lower'.| |'trim(null)'|Invalid argument #0 of type null for function 'trim': expected string| |'Number(false)'|Invalid argument #0 of type boolean for function 'Number': expected number,string| |'hello(false)'|Unknown function: 'hello'| |'123(false)'|Cannot handle compound expressions.| |'String("123")'|true| |'String(123)'|true| |'String("0")'|true| |'String(0)'|true| |'Number("123")'|true| |'Number(123)'|true| |'Number("0")'|false| |'Number(0)'|false| |'Number("hello there")'|Error converting value 'hello there' to number| |'Boolean("123")'|true| |'Boolean(123)'|true| |'Boolean("0")'|true| |'Boolean(0)'|false| |'Boolean("hello there")'|true| |'Boolean("")'|false| |'Boolean(Number(String(0)))'|false| |'Boolean(Number(String(1)))'|true| |'round("asd")'|Invalid argument #0 of type string for function 'round': expected number| |'round("13")'|Invalid argument #0 of type string for function 'round': expected number| |'round(13)'|true| |'round(13) == round(13.1222)'|true| |'round(13) != round(13.9922)'|true| |'round(13) == floor(13.9922)'|true| |'floor(13E8)'|true| |'floor(1359 / 342)'|true| |'upper("alon") == "ALON"'|true| |'upper("asd") != "ALON"'|true| |'upper("asd") != 333'|The operator != cannot be used with string,number. It can only be used with the types: number,string,boolean| |'lower("DIAMANT") == "diamant"'|true| |'lower("asd") != "ALON"'|true| |'lower("ASD") == "asd"'|true| |'trim(" ASD ") == "ASD"'|true| |'trim(lower(" ASD ")) == "asd"'|true| |'lower(trim(" ASD ")) == "asd"'|true| |'trimLeft(" ASD ") == "ASD "'|true| |'trimRight(" ASD ") == " ASD"'|true| |'replace("test me and you", "me", "her") == "test her and you"'|true| |'replace("test ME and you", "me", "her") == "test ME and you"'|true| |'replace("test ME and you", 123, "her") == "test ME and you"'|Invalid argument #1 of type number for function 'replace': expected string| |'replace("test ME and you", 123) == "test ME and you"'|Expected 3 arguments for function 'replace'.| |'replace("test ME and you", 123, 234, "her") == "test ME and you"'|Expected 3 arguments for function 'replace'.| |'substring("test ME and you", 0, 4) == "test"'|true| |'substring("test ME and you", 4, 8) == " ME "'|true| |'substring("test ME and you", 4, null) == " ME and you"'|Invalid argument #2 of type null for function 'substring': expected number| |'substring("test ME and you", 4, -1) == " ME and you"'|true| |'length("hello") == 5'|true| |'length(12345) == 5'|Invalid argument #0 of type number for function 'length': expected string| |'includes("team", "i")'|false| |'includes("team", "ea")'|true| |'includes("team", 456)'|Invalid argument #1 of type number for function 'includes': expected string| |'indexOf("team", "i") == -1'|true| |'indexOf("team", "ea") == 1'|true| |'indexOf("team", 456)'|Invalid argument #1 of type number for function 'indexOf': expected string| |'indexOf(234234, "234")'|Invalid argument #0 of type number for function 'indexOf': expected string| |'indexOf(String(999234234.23423), "234")'|true| |'match("hello there you", "..ll.", false)'|true| |'match("hello there you", "..LL.", false)'|false| |'match("hello there you", "hell$", true)'|false| |'match("hello there you", "^hell", true)'|true| |'match("hello there you", "bye", false)'|false| |'match("hello there you", 123, false)'|Invalid argument #1 of type number for function 'match': expected string| |'match(457457, 123, false)'|Invalid argument #0 of type number for function 'match': expected string| |'match("hello there you", "^hell", null)'|Invalid argument #2 of type null for function 'match': expected boolean| |'match(123, false)'|Expected 3 arguments for function 'match'.| |'match()'|Expected 3 arguments for function 'match'.| |'match( lower(String(round(99.234234)) + " is the number to call") + " in case of emergencies", "100", true) == ( 99 * 2000 > 99 * 999 && trueBooleanValue && somePositiveNumericValue < someNegativeNumericValue) '|true| |'match(author.name, "alon", true) && author.github.repositories > 10 && Number(substring(company.phoneNumber, 1, 4)) / 2 == 486'|true| |'hello there.testVariable == 567'|Cannot handle compound expressions.| |'hello there.badly-named-variable == 890'|Cannot handle compound expressions.| |'Variable("hello there").testVariable == 567'|Invalid identifier: 'hello there'| |'Member(Variable("hello there"), "badly-named-variable") == 890'|Invalid identifier: 'hello there'| |'Variable("author").name == "Alon Diamant"'|true| |'Member(author.github, "repositories") == 12'|true| |'author.toString'|Undefined identifier member: 'toString'| |'author.eval("")'|Invalid function name type: 'MemberExpression'|

Available gulp tasks

gulp lint - runs eslint
gulp test:unit - runs mocha unit tests
gulp coverage - runs unit tests and generates coverage report
gulp test:integration - runs karma tests
gulp test - runs unit and integration tests and generates code coverage report
gulp - default task, runs lint and test

Running tests

Install dev dependencies and run the test:

$ npm install -d && gulp

Author

Alon Diamant (advance512)