Formula Functions

Function Declaration and Execution Context

Formulas are JavaScript functions defined in the formulas object within your risksheet.json configuration. Each formula receives an info parameter containing the execution context:

Property	Type	Description
`info.item`	object	Complete work item data with all column bindings as key-value pairs
`info.value`	any	Current cell value (for display-time formulas)
`info.cell`	HTMLElement	DOM element of the cell being rendered
`info.row`	number	Zero-based row index in the grid
`info.grid`	FlexGrid	Reference to the Wijmo FlexGrid control

// Example formula structure
formulas.myFormula = function(info) {
  // Access other columns via info.item
  var occ = info.item['occurrence'];
  var sev = info.item['severity'];
  var det = info.item['detection'];
  
  // Perform calculation
  var result = occ * sev * det;
  
  // Return null for empty calculations to avoid displaying 0
  return result ? result : null;
}

Built-in Function Categories

Arithmetic Operations

Perform mathematical calculations on numeric columns.

Function	Operators	Example	Result
Addition	`+`	`info.item['cost'] + 100`	Sum of values
Subtraction	`-`	`info.item['original'] - info.item['reduction']`	Difference
Multiplication	`*`	`info.item['occ'] * info.item['sev']`	Product
Division	`/`	`info.item['total'] / info.item['count']`	Quotient
Modulo	`%`	`info.item['value'] % 2`	Remainder
Power	`Math.pow()`	`Math.pow(info.item['base'], 2)`	Exponent

Comparison Operators

Compare values to make conditional decisions in formulas.

Operator	Usage	Returns	Example
`==`	Equality	boolean	`info.item['status'] == 'Active'`
`!=`	Inequality	boolean	`info.item['priority'] != 'Low'`
`>`	Greater than	boolean	`info.item['rpn'] > 200`
`<`	Less than	boolean	`info.item['cost'] < 5000`
`>=`	Greater or equal	boolean	`info.item['sev'] >= 8`
`<=`	Less or equal	boolean	`info.item['occ'] <= 3`

Ternary Conditional

Return different values based on conditions.

// Syntax: condition ? trueValue : falseValue
formulas.riskLevel = function(info) {
  var rpn = info.item['rpn'];
  return rpn > 350 ? 'High' : (rpn > 150 ? 'Medium' : 'Low');
}

Logical Operators

Combine multiple conditions in formula logic.

Operator	Usage	Example
`&&` (AND)	Both conditions true	`info.item['sev'] > 7 && info.item['occ'] > 5`
`\|\|` (OR)	Either condition true	`info.item['status'] == 'Open' \|\| info.item['overdue'] == true`
`!` (NOT)	Negates condition	`!info.item['resolved']`

Risk Priority Number (RPN) Calculation

The most common FMEA formula multiplies three severity metrics to calculate risk priority:

// Initial RPN - before mitigations
formulas.commonRpn = function(info) {
  var value = info.item['occ'] * info.item['det'] * info.item['sev'];
  return value ? value : null;
}

// Revised RPN - after mitigations applied
formulas.commonRpnNew = function(info) {
  var value = info.item['occNew'] * info.item['detNew'] * info.item['sevNew'];
  return value ? value : null;
}

Always return null for empty calculations instead of 0 or empty string. This prevents displaying misleading zero values and maintains clean visual formatting in your grid.

String and Array Functions

String Operations

Function	Purpose	Example
`.toUpperCase()`	Convert to uppercase	`info.item['title'].toUpperCase()`
`.toLowerCase()`	Convert to lowercase	`info.item['category'].toLowerCase()`
`.substring()`	Extract substring	`info.item['id'].substring(0, 5)`
`.indexOf()`	Find position	`info.item['description'].indexOf('error')`
`.split()`	Split into array	`info.item['tags'].split(',')`

Array Operations

Function	Purpose	Example
`.length`	Get array size	`info.item['tasks'].length`
`.includes()`	Check if contains	`info.item['status'].includes('Review')`
`.filter()`	Filter elements	`info.item['items'].filter(x => x.active)`
`.map()`	Transform elements	`info.item['numbers'].map(x => x * 2)`
`.join()`	Combine to string	`info.item['labels'].join(', ')`

Mathematical Functions

Access JavaScript’s Math object for advanced calculations:

Function	Purpose	Example
`Math.round()`	Round to nearest integer	`Math.round(info.item['average'])`
`Math.floor()`	Round down	`Math.floor(info.item['value'])`
`Math.ceil()`	Round up	`Math.ceil(info.item['value'])`
`Math.abs()`	Absolute value	`Math.abs(info.item['variance'])`
`Math.min()`	Minimum value	`Math.min(a, b, c)`
`Math.max()`	Maximum value	`Math.max(info.item['scores'])`
`Math.sqrt()`	Square root	`Math.sqrt(info.item['variance'])`

Formula Execution Flow

Formula Configuration Reference

Property	Type	Required	Description
`formula`	string	Yes	Function name to call from the formulas object (e.g., `'commonRpn'`)
`type`	string	No	Column data type; formula columns auto-detect as their result type
`readOnly`	boolean	No	Formula columns are read-only by default; set explicitly to allow editing
`binding`	string	No	Column binding path; auto-generated from column ID if not specified
`header`	string	Yes	Display name for the calculated column
`width`	number	No	Column width in pixels

Type Coercion in Formulas

JavaScript automatically coerces types in formula expressions:

Operation	Input Types	Result Type	Example
Arithmetic	`number` + `number`	`number`	`5 + 3` = `8`
String Concatenation	`string` + any	`string`	`'Value: ' + 42` = `'Value: 42'`
Comparison	any == any	`boolean`	`'5' == 5` = `true`
Logical	any && any	`boolean`	`0 && true` = `false`

Ensure numeric columns contain valid numbers. Empty strings, undefined, or non-numeric values in arithmetic operations return NaN. Use conditional checks to validate data before calculations.

Performance Considerations

Formulas execute for every cell in every row during grid rendering. Optimize performance by:

Avoiding complex nested calculations when simple arithmetic suffices
Using early returns to exit calculations when intermediate results are null
Limiting array operations (filter, map) to small datasets
Caching frequently computed values using hidden columns
Minimizing DOM manipulation (accessing info.cell) in hot-path formulas

Common Patterns

Weighted Scoring

formulas.weightedScore = function(info) {
  var w1 = info.item['metric1'] * 0.5;
  var w2 = info.item['metric2'] * 0.3;
  var w3 = info.item['metric3'] * 0.2;
  return w1 + w2 + w3;
}

Conditional Escalation

formulas.escalationLevel = function(info) {
  if (info.item['severity'] >= 8 && info.item['duration'] > 30) {
    return 'Critical';
  } else if (info.item['severity'] >= 6 || info.item['impact'] == 'Major') {
    return 'High';
  }
  return 'Normal';
}

Getting Started

Concepts

Reference

Guides

Troubleshooting

FAQ

Function Declaration and Execution Context

Built-in Function Categories

Arithmetic Operations

Comparison Operators

Ternary Conditional

Logical Operators

Risk Priority Number (RPN) Calculation

String and Array Functions

String Operations

Array Operations

Mathematical Functions

Formula Execution Flow

Formula Configuration Reference

Type Coercion in Formulas

Performance Considerations

Common Patterns

Weighted Scoring

Conditional Escalation

See Also

Getting Started

Concepts

Reference

Guides

Troubleshooting

FAQ

​Function Declaration and Execution Context

​Built-in Function Categories

​Arithmetic Operations

​Comparison Operators

​Ternary Conditional

​Logical Operators

​Risk Priority Number (RPN) Calculation

​String and Array Functions

​String Operations

​Array Operations

​Mathematical Functions

​Formula Execution Flow

​Formula Configuration Reference

​Type Coercion in Formulas

​Performance Considerations

​Common Patterns

​Weighted Scoring

​Conditional Escalation

​See Also

Function Declaration and Execution Context

Built-in Function Categories

Arithmetic Operations

Comparison Operators

Ternary Conditional

Logical Operators

Risk Priority Number (RPN) Calculation

String and Array Functions

String Operations

Array Operations

Mathematical Functions

Formula Execution Flow

Formula Configuration Reference

Type Coercion in Formulas

Performance Considerations

Common Patterns

Weighted Scoring

Conditional Escalation

See Also