@@ -5,21 +5,28 @@ import { ASTNode, ArrayLiteralNode, Token, TokenType, ValidFuncNames } from "./F
55
66export class FormulaEvaluation {
77 private webUrl : string ;
8- constructor ( context : IContext , webUrlOverride ?: string ) {
9- sp . setup ( { pageContext : context . pageContext } ) ;
10- this . webUrl = webUrlOverride || context . pageContext . web . absoluteUrl ;
8+ private _meEmail : string ;
9+
10+ constructor ( context ?: IContext , webUrlOverride ?: string ) {
11+ if ( context ) {
12+ sp . setup ( { pageContext : context . pageContext } ) ;
13+ this . _meEmail = context . pageContext . user . email ;
14+ }
15+ this . webUrl = webUrlOverride || context ?. pageContext . web . absoluteUrl || '' ;
1116 }
1217
1318 /** Evaluates a formula expression and returns the result, with optional context object for variables */
1419 public evaluate ( expression : string , context : { [ key : string ] : any } = { } ) : any {
15- const tokens : Token [ ] = this . _tokenize ( expression , context ) ;
16- const postfix : Token [ ] = this . _shuntingYard ( tokens ) ;
17- const ast : ASTNode = this . _buildAST ( postfix ) ;
20+ context [ 'me' ] = this . _meEmail ;
21+ context [ 'today' ] = new Date ( ) ;
22+ const tokens : Token [ ] = this . tokenize ( expression , context ) ;
23+ const postfix : Token [ ] = this . shuntingYard ( tokens ) ;
24+ const ast : ASTNode = this . buildAST ( postfix ) ;
1825 return this . evaluateASTNode ( ast , context ) ;
1926 }
2027
2128 /** Tokenizes an expression into a list of tokens (primatives, operators, variables, function names, arrays etc) */
22- private _tokenize ( expression : string , context : { [ key : string ] : any } ) : Token [ ] {
29+ public tokenize ( expression : string , context : { [ key : string ] : any } = { } ) : Token [ ] {
2330 // Each pattern captures a different token type
2431 // and are matched in order
2532 const patterns : [ RegExp , TokenType ] [ ] = [
@@ -89,7 +96,7 @@ export class FormulaEvaluation {
8996 return tokens ;
9097 }
9198
92- private _shuntingYard ( tokens : Token [ ] ) : Token [ ] {
99+ public shuntingYard ( tokens : Token [ ] ) : Token [ ] {
93100
94101 /** Returns a precedence value for a token or operator */
95102 function getPrecedence ( op : string ) : { precedence : number , associativity : "left" | "right" } {
@@ -234,7 +241,7 @@ export class FormulaEvaluation {
234241 }
235242 }
236243
237- private _buildAST ( postfixTokens : Token [ ] ) : ASTNode {
244+ public buildAST ( postfixTokens : Token [ ] ) : ASTNode {
238245
239246 // Tokens are arranged on a stack/array of node objects
240247 const stack : ( Token | ASTNode | ArrayLiteralNode ) [ ] = [ ] ;
@@ -287,7 +294,7 @@ export class FormulaEvaluation {
287294 return stack [ 0 ] as ASTNode ;
288295 }
289296
290- public evaluateASTNode ( node : ASTNode | ArrayLiteralNode | string | number , context : { [ key : string ] : any } ) : any {
297+ public evaluateASTNode ( node : ASTNode | ArrayLiteralNode | string | number , context : { [ key : string ] : any } = { } ) : any {
291298
292299 if ( ! node ) return 0 ;
293300
@@ -430,17 +437,17 @@ export class FormulaEvaluation {
430437 return arrayToJoin . join ( separator ) ;
431438 }
432439 case 'substring' : {
433- const mainStrSubstring = funcArgs [ 0 ] ;
434- const start = funcArgs [ 1 ] ;
435- const end = funcArgs [ 2 ] ;
440+ const mainStrSubstring = funcArgs [ 0 ] || '' ;
441+ const start = funcArgs [ 1 ] || 0 ;
442+ const end = funcArgs [ 2 ] || mainStrSubstring . length ;
436443 return mainStrSubstring . substr ( start , end ) ;
437444 }
438445 case 'toUpperCase' : {
439- const strToUpper = funcArgs [ 0 ] ;
446+ const strToUpper = funcArgs [ 0 ] || '' ;
440447 return strToUpper . toUpperCase ( ) ;
441448 }
442449 case 'toLowerCase' : {
443- const strToLower = funcArgs [ 0 ] ;
450+ const strToLower = funcArgs [ 0 ] || '' ;
444451 return strToLower . toLowerCase ( ) ;
445452 }
446453 case 'startsWith' : {
@@ -600,14 +607,32 @@ export class FormulaEvaluation {
600607
601608 return 0 ; // Default fallback
602609 }
610+
611+ public validate ( expression : string ) : boolean {
612+ const validFunctionRegex = `(${ ValidFuncNames . map ( fn => `${ fn } ) . join ( '|' ) } ;
613+ const pattern = new RegExp ( `^(?:@\\w+|\\[\\$?[\\w+.]\\]|\\d+(?:\\.\\d+)?|"(?:[^"]*)"|'(?:[^']*)'|${ validFunctionRegex } ) ;
614+
615+ /* Explanation -
616+ /@\\w+/ matches variables specified by the form @variableName.
617+ /\\[\\$?\\w+\\/] matches variables specified by the forms [variableName] and [$variableName].
618+ /\\d+(?:\\.\\d+)?/ matches numbers, including decimal numbers.
619+ /"(?:[^"]*)"/ and /'(?:[^']*)'/ match string literals in double and single quotes, respectively.
620+ /${validFunctionRegex}/ matches valid function names.
621+ /\\?/ matches the ternary operator ?.
622+ /:/ matches the colon :.
623+ /[+\\-*/ //<>=%!&|?:,()\\[\\]]/ matches operators.
624+
625+ return pattern . test ( expression ) ;
626+ }
627+
603628 private _getSharePointThumbnailUrl ( imageUrl : string ) : string {
604629 const filename = imageUrl . split ( '/' ) . pop ( ) ;
605630 const url = imageUrl . replace ( filename , '' ) ;
606631 const [ filenameNoExt , ext ] = filename . split ( '.' ) ;
607- return `${ url } / _t/${ filenameNoExt } ${ ext } ;
632+ return `${ url } ${ filenameNoExt } ${ ext } ;
608633 }
609634 private _getUserImageUrl ( userEmail : string ) : string {
610- return `${ this . webUrl } username =${ userEmail }
635+ return `${ this . webUrl } accountname =${ userEmail }
611636 }
612637}
613638
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