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.
npm install @codefresh-io/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.
* 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
``bash`
$ npm install cf-expression-evaluator --save
`js
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
)
);
`
|Type|Example|True/False|
|----|:-----:|:--------:|
|String|\"hello\"
'there'|Empty string is false: ''
Non-empty string is true: 'something'
String comparison is lexicographic|
|Number|5
3.4
1.79E+308|0 is false
any non-0 number is true|
|Boolean|true
false|true is true
false is false|
|null|Null|always false|
* 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.
|Operator|Operation|
|--------|:-------:|
|-|Negation of numbers|
|!|Logical NOT|
|Operator|Operation|
|--------|:-------:|
|+|Add, String Concatenation|
|-|Subtract|
|*|Multiply|
|/|Divide|
|%|Modulus|
|&&|Logical AND|
||||Logical OR|
|Operator|Operation|
|--------|:-------:|
|==|Equal|
|!=|Not equal|
|>|Greater than|
|>=|Greater than or equal|
|<|Less than|
|>=|Less than or equal|
|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') == 50
Number('hello') is invalid|
|Boolean|0: number or string|boolean of input value|Boolean('123') == true
Boolean('') == false
Boolean(583) == true
Boolean(0) == false|
|round|0: number|rounded number|round(1.3) == 1
round(1.95) == 2|
|floor|0: number|number rounded to floor|floor(1.3) == 1
floor(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 string
1: string - substring to find
2: 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 string
1: string - index to start
2: 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 string
1: string - string to search for|whether a search string is found inside the main string|includes(\"codefresh\", \"odef\") == true|
|indexOf|0: string - main string
1: 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 string
1: string - regular expression string, JS style
2: boolean - ignore case|search for a regular expression inside a string, ignoring or not ignoring case|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|
|Variable|string|Lookup the value of a variable|Variable('someVariable')|
|Member|0: string - variable name
1: string - member name|Lookup the value of a member of a variable|Member('someVariable', 'workingDirectory')|
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'|
* 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
Install dev dependencies and run the test:
``sh``
$ npm install -d && gulp
Alon Diamant (advance512)
Copyright © 2016, Codefresh.
Released under the MIT license.
*