Function generateFilterFn

Extension/src/Utility/Eventing/eventParser.ts:134–255

(scanner: Scanner)

const sandbox = new Sandbox();

function generateFilterFn(scanner: Scanner): Filter {
    // take all the tokens until we hit a closing bracket
    const inner = [...scanner.takeUntil(Kind.CloseBracket, {
        nestable: [[Kind.OpenBracket, Kind.CloseBracket]],
        escape: [Kind.Backslash]
    })];

    // a filter expression is one or more of:
    //  - a regular expression
    //  - a JavaScript expression
    // separated by && or ||
    const expression = new Array<string>();

    // remove leading whitespace
    eatWhitespace(inner);

    outer:
    while (inner.length) {
        eatWhitespace(inner);
        let token = inner.shift()!;

        switch (token.kind) {
            case Kind.Slash: {
                // regular expression
                // take all tokens until we hit a slash that isn't escaped
                const rxExpression = [token];

                while (inner.length) {

                    token = inner.shift()!;
                    rxExpression.push(token); // store this token as part of the regex

                    switch (token.kind) {
                        case Kind.Slash:
                            // now see if there are any flags
                            if (inner.length) {
                                token = inner[0];
                                if (token.kind === Kind.Identifier) {
                                    rxExpression.push(inner.shift()!);
                                }
                            }
                            // at this point, we should have the whole regex.
                            // turn this into an expression that tests against any $strings
                            expression.push(`(!!$strings.find( ($text)=> { const r = ${rxExpression.map(token => token.text).join('')}.exec($text); if( r ) { $captures.push( ...r ); return true; } } ))`);
                            continue outer;

                        case Kind.Backslash:
                            // take the next token, and add it to the regex
                            rxExpression.push(inner.shift()!);
                            continue;
                    }

                    // if we have nothing left, and we haven't closed the regex, then it's an error
                    if (!inner.length) {
                        throw new Error(`unterminated regular expression ${inner}`);
                    }
                }
            }