ExprManager

Installation

npm install expr-manager

Usage

Simple calculation

var exprManager = new ExprManager();

var expr = "0.1 + 0.2";
var v = exprManager.calc(expr);
if (!v.errorMsg) {
    console.log(v.toValue());
    // => 0.3
} else {
    console.log(v.errorMsg);
}

var calcData = {v1: "hello", v2: "world"};
expr = "v1 + ' ' + v2 + '!'";
v = exprManager.calc(expr, calcData);
console.log(v.toValue());
// => "hello world!"

expr = "IIf(1 > 2, 'a', 'b')";
v = exprManager.calc(expr);
console.log(v.toValue());
// => "b"

expr = "123.ToString()"
v = exprManager.calc(expr);
console.log(v.toValue());
// => "123"

Advanced calculation

var dataContext = {
    "Table": {
        fields: {
            "Field0": { type: "number", primaryKey: true },
            "Field1": { type: "string" },
            "Field2": { type: "object" },
            "Field3": { type: "array" },
            "Field4": { type: "date" },
            "Field5": { type: "boolean" },
            "CalcField0": { type: "string" },
            "CalcField1": { type: "string" }
        },
        childs: {
            "SubTable": {
                fields: {
                    "Field0": { type: "number", primaryKey: true },
                    "Field1": { type: "string" },
                    "Field2": { type: "object" },
                    "Field3": { type: "array" },
                    "Field4": { type: "date" },
                    "Field5": { type: "boolean" }
                }
            }
        }
    }
};
var data = {
    Table: [{
        Field0: 0,
        Field1: "Hello",
        Field2: {key: "i", value: 0},
        Field3: [0, 1],
        Field4: new Date(),
        Field5: false,
        SubTable: [{
            Field0: 0,
            Field1: "Wrold",
            Field2: {key: "j", value: 10},
            Field3: [2, 3],
            Field4: new Date(),
            Field5: true
        }]
    }]
};
var context = {
    Field0: "!"
};

exprManager.init(data, dataContext, context);

var tableName = "Table";
var dataCursor = {
    "Table": 0,
    "Table.SubTable": 0
};
expr = "Field1 + ' ' + SubTable[0].Field1 + $C.Field0";
v = exprManager.calcExpr(expr, tableName, dataCursor);
console.log(v.toValue());
// => "Hello World!"

var t = exprManager.calcDependencies(expr, tableName);
console.log(t.dependencies);
// => ["Table.Field1", "Table.SubTable", "Table.SubTable.Field1"]

Advanced dependent calculation

exprManager.resetExpression();

var doCalc = function(type, info) {
    console.log(type);
};

exprManager.addExpression("Field1 + ' ' + SubTable[0].Field1",
    "Table", "CalcField0", ["load", "add", "update", "remove"],
    doCalc, null);
exprManager.addExpression("CalcField0 + SubTable.Count().ToString()",
    "Table", "CalcField1", ["load", "add", "update", "remove"],
    doCalc, null);

var errorMsg = exprManager.checkAndSort();
if (!errorMsg) {
    exprManager.calcExpression("load", {
        entityName: "Table"
    });
    // doCalc => "load"

    exprManager.calcExpression("add", {
        entityName: "Table"
    });
    // doCalc => "add"
    
    exprManager.calcExpression("update", {
        entityName: "Table",
        propertyName: "Field1"
    });
    // doCalc => "update"

    exprManager.calcExpression("remove", {
        entityName: "Table.SubTable"
    });
    // doCalc => "remove"
} else {
    console.log(errorMsg)
}

Value type

| Type | Value | | ----------- | ----------------------------------------- | | string | "value1" 'value2' | | number | 1 -1 1.23 -1.23 | | boolean | true false | | date | Now() "2017-10-24T10:10:10.037Z".ToDate() | | object | {a: 1, b: 2} {a: "1", b: "2"} | | array | [1,2] ["1","2"] | | null | null |

Operator precedence

| Operator | Description | | --------------- | ------------------------------------------------------------------ | | . [] () {} | Member access, array, grouping, object | | + - ! | Unary operators, logical NOT | | * / % | Multiplication, division, modulo division | | + - | Addition, subtraction | | < <= > >= | Less than, less than or equal, greater than, greater than or equal | | == != | Equality, inequality | | && | Logical AND | | || | Logical OR | | : | Colon operator | | , | Multiple evaluation |

System functions

| Owner | Functions | | ------- | --------------------------------------------------------------------------- | | | FieldDisplayName FieldName FieldValue IIf IfNull Now Parent PropValue Random RecNo Root | | array | Average Count Distinct Max Min Sum Where | | boolean | ToString | | date | DateOf DayOf DayOfWeek DaysBetween HourOf HoursBetween IncDay IncHour IncMinute IncMonth IncSecond IncWeek IncYear MilliSecondOf MilliSecondsBetween MinuteOf MinutesBetween MonthOf MonthsBetween SecondOf SecondsBetween ToString WeekOf WeeksBetween YearOf YearsBetween | | number | Abs Ceil Cos Exp Floor Ln Log Power Round Sin Sqrt Tan ToRMB ToString Trunc | | object | Parent RecNo | | string | LeftString Length Lower Pos Replace ReplaceReg RightString SubString ToDate ToNumber ToString Trim TrimLeft TrimRight Upper |

Example

npm install
npm start
open example/index.html

License

expr-manager.js is freely distributable under the terms of the MIT license.